1&#39;-substituted pyrimidine n-nucleoside analogs for antiviral treatment

ABSTRACT

Provided are compounds of Formula I: 
     
       
         
         
             
             
         
       
     
     nucleosides, nucleoside phosphates and prodrugs thereof, wherein R 6  is CN, ethenyl, 2-haloethen-1-yl, or (C 2 -C 8 )-alkyn-1-yl. The compounds, compositions, and methods provided are useful for the treatment of Flaviviridae virus infections.

This application claims the benefit of U.S. provisional application No.61/474,848, filed Apr. 13, 2011, under 35 U.S.C. 111 (b).

FIELD OF THE INVENTION

The invention relates generally to compounds with antiviral activity,more particularly nucleosides active against Flaviviridae,Paramyxoviridae, Orthomyxoviridae, and Picornaviridae virus infections.

BACKGROUND OF THE INVENTION

Viruses comprising the Flaviviridae family comprise at least threedistinguishable genera including pestiviruses, flaviviruses, andhepaciviruses (Calisher, at al., J. Gen. Virol., 1993, 70, 37-43). Whilepestiviruses cause many economically important animal diseases such asbovine viral diarrhea virus (BVDV), classical swine fever virus (CSFV,hog cholera) and border disease of sheep (BDV), their importance inhuman disease is less well characterized (Moennig, V., et al., Adv. Vir.Res. 1992, 48, 53-98). Flaviviruses are responsible for important humandiseases such as dengue fever and yellow fever, while hepacivirusescause hepatitis C virus infections in humans. Other important viralinfections caused by the Flaviviridae family include West Nile virus(WNV) Japanese encephalitis virus (JEV), tick-borne encephalitis virus,Junjin virus, Murray Valley encephalitis, St. Louis encephalitis, Omskhemorrhagic fever virus and Zika virus. Combined, infections from theFlaviviridae virus family cause significant mortality, morbidity andeconomic losses throughout the world. Therefore, there is a need todevelop effective treatments for Flaviviridae virus infections.

One common member of the Flaviviridae family is hepatitis C virus (HCV).HCV is the leading cause of chronic liver disease worldwide (Boyer, N.et al. J Hepatol. 32:98-112, 2000) so a significant focus of currentantiviral research is directed toward the development of improvedmethods of treatment of chronic HCV infections in humans (Di Besceglie,A. M. and Bacon, B. R., Scientific American, Oct.: 80-85, (1999);Gordon, C. P., et al., J. Med. Chem. 2005, 48, 1-20; Maradpour, D.; etal., Nat. Rev. Micro. 2007, 5(6), 453-463). A number of HCV treatmentsare reviewed by Bymock et al. in Antiviral Chemistry & Chemotherapy,11:2; 79-95 (2000).

RNA-dependent RNA polymerase (RdRp) is one of the best-studied targetsfor the development of novel HCV therapeutic agents. The NS5B polymeraseis a target for inhibitors in early human clinical trials (Sommadossi,J., WO 01/90121 A2, US 2004/0006002 A1). These enzymes have beenextensively characterized at the biochemical and structural level, withscreening assays for identifying selective inhibitors (De Clercq, E.(2001) J. Pharmacol. Exp. Ther. 297:1-10; De Clercq, E. (2001) J. Clin.Virol. 22:73-89). Biochemical targets such as NS5B are important indeveloping HCV therapies since HCV does not replicate in the laboratoryand there are difficulties in developing cell-based assays andpreclinical animal systems.

Currently, there are primarily two antiviral compounds, ribavirin, anucleoside analog, and interferon-alpha (α) (IFN), that are used for thetreatment of chronic HCV infections in humans. Ribavirin alone is noteffective in reducing viral RNA levels, has significant toxicity, and isknown to induce anemia. The combination of IFN and ribavirin has beenreported to be effective in the management of chronic hepatitis C(Scott, L. J., et al. Drugs 2002, 62, 507-556), but less than half thepatients given this treatment show a persistent benefit. Other patentapplications disclosing the use of nucleoside analogs to treat hepatitisC virus include WO 01/32153, WO 01/60315, WO 02/057425, WO 02/057287, WO02/032920, WO 02/18404, WO 04/046331, WO2008/089105 and WO2008/141079,but additional treatments for HCV infections have not yet becomeavailable for patients.

Virologic cures of patients with chronic HCV infection are difficult toachieve because of the prodigious amount of daily virus production inchronically infected patients and the high spontaneous mutability of HCVvirus (Neumann, et al., Science 1998, 282, 103-7; Fukimoto, et al.,Hepatology, 1996, 24, 1351-4; Domingo, et al., Gene, 1985, 40, 1-8;Martell, et al., J. Virol. 1992, 66, 3225-9. Experimental anti-viralnucleoside analogs have been shown to induce viable mutations in the HCVvirus both in vivo and in vitro (Migliaccio, et al., J. Biol. Chem.2003, 926; Carroll, et al., Antimicrobial Agents Chemotherapy 2009, 926;Brown, A. B., Expert Opin. Investig. Drugs 2009, 18, 709-725).Therefore, drugs having improved antiviral properties, particularlyenhanced activity against resistant strains of virus, improved oralbioavailability, fewer undesirable side effects and extended effectivehalf-life in vivo (De Francesco, R. et al. (2003) Antiviral Research58:1-16) are urgently needed.

Anti HCV 2′-deoxy-2′-fluoro-nucleosides and nucleotides have beendisclosed by Sofia (WO/2008/121634), Attenni (WO/2008/142055), Narjes(WO/2008/085508), Wang (WO/2006/012440), Clark (WO/2005/003147) andSommadossi (WO/2004/002999) but none of these compounds have becomeavailable for patients.

Influenza viruses of the Orthomyxoviridae family that belong to thegenera A and B are responsible for seasonal flu epidemics each year,which cause acute contagious respiratory infections. Children, the old,and people with chronic diseases are at high risk to develop severecomplications that lead to high morbidity and mortality rates (Memoli etal., Drug Discovery Today 2008, 13, 590-595). Among the three influenzagenera, type A viruses are the most virulent human pathogens that causethe most severe disease, can be transmitted to other species, and giverise to human influenza pandemics. The recent human influenza outbreakof the aggressive porcine A/H1N1 strain in 2009 has emphasized the needfor novel antiviral therapeutics. While yearly vaccination programs arecurrently used to protect populations from influenza infection, theseprograms must anticipate the virus strains that will be prevalent duringseasonal outbreaks to be effective and they do not address the problemof sudden, unanticipated influenza pandemics. The recent human influenzaoutbreak of the aggressive porcine A/H1N1 strain in 2009 is an exampleof this problem. Therefore there is a continuing need for novelanti-influenza therapeutics.

SUMMARY OF THE INVENTION

Provided are compounds that inhibit viruses of the Flaviviridae family.The invention also comprises compounds of Formula I that inhibit viralnucleic acid polymerases, particularly HCV RNA-dependent RNA polymerase(RdRp), rather than cellular nucleic acid polymerases. Without wishingto be bound by theory, the compounds of the invention may inhibit viralRNA-dependent RNA polymerase and thus inhibit the replication of thevirus. Compounds of the invention are useful for treating Flaviviridaeinfections, including hepatitis C, in humans and other animals. It hasbeen surprisingly found that when R⁶ is other than hydrogen, such as,for example, cyano, alkenyl, or alkynyl, compounds have improvedcellular selectivity. This is further explained in the examples below.

In one embodiment, provided are compounds of Formula I:

or a pharmaceutically acceptable salt thereof;

wherein:

Base is a naturally occurring or modified pyrimidine base;

R¹ is H, CN, OR^(a), (C₁-C₄)alkyl, (C₁-C₄)substituted alkyl,(C₂-C₄)alkenyl, (C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl,(C₂-C₄)substituted alkynyl or S(O)_(n)R^(a);

R² is H, OR^(a), N(R^(a))₂, N₃, CN, NO₂, S(O)_(n)R^(a), (C₁-C₄)alkyl,(C₄-C₆)cycloalkylalkyl, (C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl,(C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl, or (C₂-C₄)substitutedalkynyl;

or R¹ and R² taken together with the carbon to which they are attachedform a 3-to 6-membered cycloalkyl ring wherein 1 to 3 carbon atoms ofsaid cycloalkyl ring is optionally replaced by O or S(O)_(n);

R³, R⁴, and R⁵ are each independently H, OR^(a), N(R^(a))₂, N₃, CN, NO₂,S(O)_(n)R^(a), halogen, (C₁-C₄)alkyl, (C₄-C₈)cycloalkylalkyl,(C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl, (C₂-C₄)substituted alkenyl,(C₂-C₄)alkynyl, or (C₂-C₄)substituted alkynyl;

or any two of R³, R⁴ or R⁵ on adjacent carbon atoms when taken togetherare —O(CO)O— or when taken together with the ring carbon atoms to whichthey are attached to form a double bond;

R⁶ is CN, ethenyl, 2-haloethen-1-yl, or (C₂-C₈)alkyn-1-yl,

each n is independently 0, 1, or 2;

each R^(a) is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, aryl(C₁-C₈)alkyl, (C₄-C₈)cycloalkylalkyl, —C(═O)R¹¹,—C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹, —S(O)₂R¹¹, —S(O)(OR¹¹),—S(O)₂(OR¹¹), or —SO₂NR¹¹R¹²;

R⁷ is H, —C(═O)R¹¹, —C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹,—S(O)₂R¹¹, —S(O)(OR¹¹), —S(O)₂(OR¹¹), —SO₂NR¹¹R¹², or the group ofFormula Ia

wherein

Y is O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂;

W¹ and W², when taken together, are —Y³(C(R^(y))₂)₃Y³—;

or one of W¹ or W² together with either R³ or R⁴ is —Y³— and the otherof W¹ or W² is Formula Ib;

or W¹ and W² are each, independently, a group of Formula Ib:

wherein:

each Y¹ is independently O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂;

each Y² is independently a bond, O, CR₂, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR),N—NR₂, S, S—S, S(O), or S(O)₂;

each Y³ is independently O, S, or NR;

M2 is 0, 1, or 2;

each R^(x) is a group of Formula Ic

wherein:

each M1a, M1c, and M1d is independently 0 or 1;

M1b is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12;

each R^(y) is independently H, F, Cl, Br, I, —CN, —N₃, —NO₂, —OR,—C(R)₂—O—C(R)₃, —C(═Y¹)R, —C(═Y¹)R¹³, —C(═Y¹)OR, —C(═Y¹)N(R)₂, —N(R)₂,—⁺N(R)₃, —SR, —S(O)R, —S(O)₂R, —S(O)₂R¹³, —S(O)(OR), —S(O)₂(OR),—OC(═Y¹)R, —OC(═Y¹)OR, —OC(═Y¹)(N(R)₂), —SC(═Y¹)R, —SC(═Y¹)OR,—SC(═Y¹)(N(R)₂), —N(R)C(═Y¹)R, —N(R)C(═Y¹)OR, —N(R)C(═Y¹)N(R)₂, —SO₂NR₂,(C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈) alkynyl, (C₆-C₂₀) aryl, (C₃-C₂₀)cycloalkyl, (C₂-C₂₀) heterocyclyl, arylalkyl, or heteroarylalkyl,

-   -   wherein each (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈) alkynyl,        (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl,        arylalkyl, or heteroarylalkyl is optionally substituted with 1-3        R²⁰ groups;    -   or when taken together, two R^(y) on the same carbon atom form a        cycloalkyl ring of 3 to 7 carbon atoms;

each R is independently H, (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈)alkynyl, (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl, orarylalkyl;

R⁸ is H, (C₁-C₄) alkyl, or (C₁-C₄) substituted alkyl;

each R¹¹ or R¹² is independently H, (C₁-C₈)alkyl, (C₂-C₆)alkenyl,(C₂-C₈)alkynyl, (C₄-C₈)cycloalkylalkyl, (C₃-C₂₀)cycloalkyl,(C₂-C₂₀)heterocyclyl, optionally substituted aryl, optionallysubstituted heteroaryl, —C(═O)(C₁-C₈)alkyl, —S(O)_(n)(C₁-C₈)alkyl oraryl(C₁-C₈)alkyl; or R¹¹ and R¹² taken together with a nitrogen to whichthey are both attached form a 3-to 7-membered heterocyclic ring whereinany one carbon atom of said heterocyclic ring can optionally be replacedwith —O—, —S— or —NR^(a)—;

each R¹³ is independently a cycloalkyl or heterocycle optionallysubstituted with 1-3 R or R²⁰ groups;

each R²⁰ is independently, halogen, CN, N₃, N(R)₂, OR, —SR, —S(O)R,—S(O)₂R, —S(O)(OR), —S(O)₂(OR), —C(═Y¹)R, —C(═Y¹)OR, or C(═Y¹)N(R)₂;

wherein each alkyl, alkenyl, alkynyl, aryl or heteroaryl of each R¹, R²,R³, R⁴, R⁵, R⁸, R¹¹ or R¹² is, independently, optionally substitutedwith 1 to 3 halo, hydroxy, CN, N₃, N(R^(a))₂ or OR^(a); and wherein 1 to3 of the non-terminal carbon atoms of each said (C_(r) C₈)alkyl may beoptionally replaced with —O—, —S— or —NR^(a)—;

with the following provisos:

a) when R¹, R³, and R⁵ are hydrogen, R² and R⁴ are hydroxy, R⁶ is cyanoand R⁷ and R⁸ are hydrogen, then Base is not uracil or thymine;

b) when R¹ and R⁴ are hydroxy, R², R³, and R⁵ are hydrogen, R⁶ is cyanoand R⁷ and R⁸ are hydrogen, then. Base is not uracil or cytosine;

c) when R¹, R², R³, and R⁵ are hydrogen, R⁴ is hydroxy, R⁶ is cyano andR⁷ and R⁸ are hydrogen, then Base is not uracil, cytosine, thymine or5-iodo-uracil;

d) when R¹, R³, and R⁵ are hydrogen, R² and R⁴ are hydroxy, R⁶ isethenyl and R⁷ and R⁸ are hydrogen, then Base is not uracil or cytosine;

e) when R⁵ is other than H, then R⁸ is H;

f) when R¹ is hydroxy, R², R³, R⁵, and R⁸ are hydrogen, R⁶ is cyano, R⁴is hydrogen or benzoyl, and R⁷ is hydrogen or benzoyl, then Base is notcytosine;

g) when R¹ is acetyl or hydroxy, R², R³, R⁵, R⁷, and R⁸ are hydrogen, R⁴is hydroxy or —OC(O)phenyl, then Base is not 2-oxo-4-hydroxypyrimidinyl;

h) when R¹ is acetoxy, R⁴ is benzoyloxy, R⁶ is cyano, R⁷ is benzoyl, andR², R³, R⁵, and R⁸ are hydrogen, then base is not uracil; and

i) at least one of R¹, R², R³, R⁴ and R⁵ is not hydrogen.

In another embodiment, provided are compounds of Formula I andpharmaceutically acceptable salts or esters thereof and all racemates,enantiomers, diastereomers, tautomers, polymorphs, pseudopolymorphs andamorphous forms thereof.

In another embodiment, provided are pharmaceutical compositionscomprising an effective amount of a Formula I compound as describedabove, or a pharmaceutically acceptable salt thereof, and apharmaceutically acceptable diluent or carrier.

In another embodiment, provided are pharmaceutical compositionscomprising a pharmaceutically acceptable diluent or carrier and aneffective amount of a compound of Formula I:

or a pharmaceutically acceptable salt thereof;

wherein:

Base is a naturally occurring or modified pyrimidine base;

R¹ is H, CN, OR^(a), (C₁-C₄)alkyl, (C₁-C₄)substituted alkyl,(C₂-C₄)alkenyl, (C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl,(C₂-C₄)substituted alkynyl or S(O)_(n)R^(a);

R² is. H, OR^(a), N(R^(a))₂, N₃, CN, NO₂, S(O)_(n)R^(a), (C₁-C₄)alkyl,(C₄-C₆)cycloalkylalkyl, (C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl,(C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl, or (C₂-C₄)substitutedalkynyl;

or R¹ and R² taken together with the carbon to which they are attachedform a 3-to 6-membered cycloalkyl ring wherein 1 to 3 carbon atoms ofsaid cycloalkyl ring is optionally replaced by O or S(O)_(n);

R³, R⁴, and R⁵ are each independently H, OR^(a), N(R^(a))₂, N₃, CN, NO₂,S(O)_(n)R^(a), halogen, (C₁-C₄)alkyl, (C₄-C₈)cycloalkylalkyl,(C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl, (C₂-C₄)substituted alkenyl,(C₂-C₄)alkynyl, or (C₂-C₄)substituted alkynyl;

or any two of R³, R⁴ or R⁵ on adjacent carbon atoms when taken togetherare —O(CO)O— or when taken together with the ring carbon atoms to whichthey are attached to form a double bond;

R⁶ is CN, ethenyl, 2-haloethen-1-yl, or (C₂-C₈)alkyn-1-yl,

each n is independently 0, 1, or 2;

each R^(a) is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, aryl(C₁-C₈)alkyl, (C₄-C₈)cycloalkylalkyl, —C(═O)R¹¹,—C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹—S(O)₂R¹¹, —S(O)(OR¹¹),—S(O)₂(OR¹¹), —SO₂NR¹¹R¹²;

R⁷ is H, —C(═O)R¹¹, —C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹,—S(O)₂R¹¹, —S(O)(OR¹¹), —S(O)₂(OR¹¹), —SO₂NR¹¹R¹², or the group ofFormula Ia

wherein

Y is O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂;

W¹ and W², when taken together, are —Y³(C(R^(y))₂)₃Y³—;

or one of W¹ or W² together with either R³ or R⁴ is —Y³— and the otherof W¹ or W² is Formula Ib;

or W¹ and W² are each, independently, a group of Formula Ib:

wherein:

each Y¹ is independently O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂;

each Y² is independently a bond, O, CR₂, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR),N—NR₂, S, S—S, S(O), or S(O)₂;

each Y³ is independently O, S, or NR;

M2 is 0, 1, or 2;

each R^(x) is a group of Formula Ic

wherein:

each M1a, M1c, and M1d is independently 0 or 1;

M1b is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12;

each R^(y) is independently H, F, Cl, Br, I, —CN, —N₃, —NO₂, —OR,—C(R)₂—O—C(R)₃, —C(═Y¹)R, —C(═Y¹)R¹³, —C(═Y¹)OR, —C(═Y¹)N(R)₂, —N(R)₂,—⁺N(R)₃, —SR, —S(O)R, —S(O)₂R, —S(O)₂R¹³, —S(O)(OR), —S(O)₂(OR),—OC(═Y¹)R, —OC(═Y¹)OR, —OC(═Y¹)(N(R)₂), —SC(═Y¹)R, —SC(═Y¹)OR,—SC(═Y¹)(N(R)₂), —N(R)C(═Y¹)R, —N(R)C(═Y¹)OR, —N(R)C(═Y¹)N(R)₂, —SO₂NR₂,(C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈) alkynyl, (C₆-C₂₀) aryl, (C₃-C₂₀)cycloalkyl, (C₂-C₂₀) heterocyclyl, arylalkyl, or heteroarylalkyl,

-   -   wherein each (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈) alkynyl,        (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl,        arylalkyl, or heteroarylalkyl is optionally substituted with 1-3        R²⁰ groups;    -   or when taken together, two R^(y) on the same carbon atom form a        cycloalkyl ring of 3 to 7 carbon atoms;

each R is independently H, (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈)alkynyl, (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl, orarylalkyl;

R⁸ is H, (C₁-C₄) alkyl, or (C₁-C₄) substituted alkyl;

each R¹¹ or R¹² is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, (C₄-C₈)cycloalkylalkyl, (C₃-C₂₀)cycloalkyl,(C₂-C₂₀)heterocyclyl, optionally substituted aryl, optionallysubstituted heteroaryl, —C(═O)(C₁-C₈)alkyl, —S(O)_(n)(C₁-C₈)alkyl oraryl(C₁-C₈)alkyl; or R¹¹ and R¹² taken together with a nitrogen to whichthey are both attached form a 3-to 7-membered heterocyclic ring whereinany one carbon atom of said heterocyclic ring can optionally be replacedwith —O—, —S— or —NR^(a)—;

each R¹³ is independently a cycloalkyl or heterocycle optionallysubstituted with 1-3 R or R²⁰ groups;

each R²⁰ is independently, halogen, CN, N₃, N(R)₂, OR, —SR, —S(O)R,—S(O)₂R, —S(O)(OR), —S(O)₂(OR), —C(═Y¹)R, —C(═Y¹)OR, or C(═Y¹)N(R)₂;

wherein each alkyl, alkenyl, alkynyl, aryl or heteroaryl of each R¹, R²,R³, R⁴, R⁵, R⁸, R¹¹ or R¹² is, independently, optionally substitutedwith 1 to 3 halo, hydroxy, CN, N₃, N(R^(a))₂ or OR^(a); and wherein 1 to3 of the non-terminal carbon atoms of each said (C₁-C₈)alkyl may beoptionally replaced with —O—, —S— or —NR^(a)—

with the proviso that at least one of R¹, R², R³, R⁴ and R⁵ is nothydrogen.

In another embodiment of the invention, is provided a method ofinhibiting HCV polymerase comprising administering to a mammal in needthereof a compound of the invention as described throughout.

In another embodiment, the present invention is directed to a method ofinhibiting HCV polymerase comprising administering to a mammal in needthereof a therapeutically effective amount of a compound of Formula I:

or a pharmaceutically acceptable salt thereof;

wherein:

Base is a naturally occurring or modified pyrimidine base;

R¹ is H, CN, OR^(a), (C₁-C₄)alkyl, (C₁-C₄)substituted alkyl,(C₂-C₄)alkenyl, (C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl,(C₂-C₄)substituted alkynyl or S(O)_(n)R^(a);

R² is H, OR^(a), N(R^(a))₂, N₃, CN, NO₂, S(O)_(n)R^(a), (C₁-C₄)alkyl,(C₄-C₆)cycloalkylalkyl, (C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl,(C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl, or (C₂-C₄)substitutedalkynyl;

or R¹ and R² taken together with the carbon to which they are attachedform a 3-to 6-membered cycloalkyl ring wherein 1 to 3 carbon atoms ofsaid cycloalkyl ring is optionally replaced by O or S(O)_(n);

R³, R⁴, and R⁵ are each independently H, OR^(a), N(R^(a))₂, N₃, CN, NO₂,S(O)_(n)R^(a), halogen, (C₁-C₄)alkyl, (C₄-C₈)cycloalkylalkyl,(C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl, (C₂-C₄)substituted alkenyl,(C₂-C₄)alkynyl, or (C₂-C₄)substituted alkynyl;

or any two of R³, R⁴ or R⁵ on adjacent carbon atoms when taken togetherare —O(CO)O— or when taken together with the ring carbon atoms to whichthey are attached to form a double bond;

R⁶ is CN, ethenyl, 2-haloethen-1-yl, or (C₂-C₈)alkyn-1-yl,

each n is independently 0, 1, or 2;

each R^(a) is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, aryl(C₁-C₈)alkyl, (C₄-C₈)cycloalkylalkyl, —C(═O)R¹¹,—C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹, —S(O)₂R¹¹, —S(O)(OR¹¹),—S(O)₂(OR¹¹), or —SO₂NR¹¹R¹²;

R⁷ is H, —C(═O)R¹¹, —C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹,—S(O)₂R¹¹, —S(O)(OR¹¹), —S(O)₂(OR¹¹), —SO₂NR¹¹R¹², or the group ofFormula Ia

wherein

Y is O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂,

W¹ and W², when taken together, are —Y³(C(R^(y))₂)₃Y³—;

or one of W¹ or W² together with either R³ or R⁴ is —Y³— and the otherof W¹ or W² is Formula Ib;

or W¹ and W² are each, independently, a group of Formula Ib:

wherein:

each Y¹ is independently O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂;

each Y² is independently a bond, O, CR₂, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR),

N—NR₂, S, S—S, S(O), or S(O)₂;

each Y³ is independently O, S, or NR;

M2 is 0, 1, or 2;

each R^(x) is a group of Formula Ic

wherein:

each M1a, M1c, and M1d is independently 0 or 1;

M1b is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12;

each R^(y) is independently H, F, Cl, Br, I, —CN, —N₃, —NO₂, —OR,—C(R)₂—O—C(R)₃, —C(═Y¹)R, —C(═Y¹)R¹³, —C(═Y¹)OR, —C(═Y¹)N(R)₂, —N(R)₂,—⁺N(R)₃, —SR, —S(O)R, —S(O)₂R, —S(O)₂R¹³, —S(O)(OR), —S(O)₂(OR),—OC(═Y¹)R, —OC(═Y¹)OR, —OC(═Y¹)(N(R)₂), —SC(═Y¹)R, —SC(═Y¹)OR,—SC(═Y¹)(N(R)₂), —N(R)C(═Y¹)R, —N(R)C(═Y¹)OR, —N(R)C(═Y¹)N(R)₂, —SO₂NR₂,(C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈) alkynyl, (C₆-C₂₀) aryl, (C₃-C₂₀)cycloalkyl, (C₂-C₂₀) heterocyclyl, arylalkyl, or heteroarylalkyl,

-   -   wherein each (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈) alkynyl,        (C₆-C₂₀) (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl, arylalkyl,        or heteroarylalkyl is optionally substituted with 1-3 R²⁰        groups;    -   or when taken together, two R^(y) on the same carbon atom form a        cycloalkyl ring of 3 to 7 carbon atoms;

each R is independently H, (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈)alkynyl, (C₈-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl, orarylalkyl;

R⁸ is H, (C₁-C₄) alkyl, or (C₁-C₄) substituted alkyl;

each R¹¹ or R¹² is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, (C₄-C₈)cycloalkylalkyl, (C₃-C₂₀)cycloalkyl,(C₂-C₂₀)heterocyclyl, optionally substituted aryl, optionallysubstituted heteroaryl, —C(═O)(C₁-C₈)alkyl, —S(O)_(n)(C₁-C₈)alkyl oraryl(C₁-C₈)alkyl; or R¹¹ and R¹² taken together with a nitrogen to whichthey are both attached form a 3-to 7-membered heterocyclic ring whereinany one carbon atom of said heterocyclic ring can optionally be replacedwith —O—, —S— or —NR^(a)—;

each R¹³ is independently a cycloalkyl or heterocycle optionallysubstituted with 1-3 R or R²⁰ groups;

each R²⁰ is independently, halogen, CN, N₃, N(R)₂, OR, —SR, —S(O)R,—S(O)₂R, —S(O)(OR), —S(O)₂(OR), —C(═Y¹)R, —C(═Y¹)OR, or C(═Y¹)N(R)₂;

wherein each alkyl, alkenyl, alkynyl, aryl or heteroaryl of each of R¹,R², R³, R⁴, R⁵, R⁸, R¹¹ or R¹² is, independently, optionally substitutedwith 1 to 3 halo, hydroxy, CN, N₃, N(R^(a))₂ or OR^(a); and wherein 1 to3 of the non-terminal carbon atoms of each said (C₁-C₈)alkyl may beoptionally replaced with —O—, —S— or —NR^(a)—;

with the proviso that at least one of R¹, R², R³, R⁴ and R⁵ is nothydrogen.

In one embodiment, the invention is directed to a method of treating aviral infection caused by a Flaviviridae virus comprising administeringto a mammal in need thereof a therapeutically effective amount of acompound or pharmaceutical composition as described above. In oneembodiment, the viral infection is caused by Hepatitis C virus.

In another embodiment, the invention is directed to a method of treatinga viral infection caused by a Paramyxoviridae virus comprisingadministering to a mammal in need thereof a therapeutically effectiveamount of a compound or pharmaceutical composition as described above.

In another embodiment, the invention is directed to a method of treatinga viral infection caused by an Orthomyxoviridae virus comprisingadministering to a mammal in need thereof a therapeutically effectiveamount of a compound or pharmaceutical composition as described above.

In still other embodiments, the invention is directed to a method oftreating a viral infection caused by a Picornaviridae virus comprisingadministering to a mammal in need thereof a therapeutically effectiveamount of a compound or pharmaceutical composition as described above.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Reference will now be made in detail to certain embodiments of theinvention, examples of which are illustrated in the accompanyingdescription, structures and formulas. While the invention will bedescribed in conjunction with the enumerated embodiments, it will beunderstood that they are not intended to limit the invention to thoseembodiments. On the contrary, the invention is intended to cover allalternatives, modifications, and equivalents, which may be includedwithin the scope of the present invention.

Compounds

In one aspect, the invention provides compounds of Formula I:

or a pharmaceutically acceptable salt thereof;

wherein:

Base is a naturally occurring or modified pyrimidine base;

R¹ is H, CN, OR^(a), (C₁-C₄)alkyl, (C₁-C₄)substituted alkyl,(C₂-C₄)alkenyl, (C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl,(C₂-C₄)substituted alkynyl or S(O)_(n)—R^(a);

R² is H, OR^(a), N(R^(a))₂, N₃, CN, NO₂, S(O)_(n)R^(a), (C₁-C₄)alkyl,(C₄-C₆)cycloalkylalkyl, (C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl,(C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl, or (C₂-C₄)substitutedalkynyl;

or R¹ and R² taken together with the carbon to which they are attachedform a 3-to 6-membered cycloalkyl ring wherein 1 to 3 carbon atoms ofsaid cycloalkyl ring is optionally replaced by O or S(O)_(n);

R³, R⁴, and R⁵ are each independently H, OR^(a), N(R^(a))₂, N₃, CN, NO₂,S(O)_(n)R^(a), halogen, (C₁-C₄)alkyl, (C₄-C₈)cycloalkylalkyl,(C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl, (C₂-C₄)substituted alkenyl,(C₂-C₄)alkynyl, or (C₂-C₄)substituted alkynyl;

or any two of R³, R⁴ or R⁵ on adjacent carbon atoms when taken togetherare —O(CO)O— or when taken together with the ring carbon atoms to whichthey are attached to form a double bond;

R⁶ is CN, ethenyl, 2-haloethen-1-yl, or (C₂-C₈)alkyn-1-yl,

each n is independently 0, 1, or 2;

each R^(a) is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, aryl(C₁-C₈)alkyl, (C₄-C₈)cycloalkylalkyl, —C(═O)NR¹¹,—C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹, —S(O)₂R¹¹, —S(O)(OR¹¹),—S(O)₂(OR¹¹), or —SO₂NR¹¹R¹²;

R⁷ is H, —C(═O)R¹¹, —C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹,—S(O)₂R¹¹, —S(O)(OR¹¹), —S(O)₂(OR¹¹), —SO₂NR¹¹R¹², or the group ofFormula Ia

wherein

Y is O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂;

W¹ and W², when taken together, are —Y³(C(R^(y))₂)₃Y³—; or one of W¹ orW² together with either R³ or R⁴ is —Y³— and the other of W¹ or W² isFormula Ib;

or W¹ and W² are each, independently, a group of Formula Ib:

wherein:

each Y¹ is independently O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂;

each Y² is independently a bond, O, CR₂, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR),N—NR₂, S, S—S, S(O), or S(O)₂;

each Y³ is independently O, S, or NR;

M2 is 0, 1, or 2;

each R^(x) is a group of Formula Ic

wherein:

each M1a, M1c, and M1d is independently 0 or 1;

M1b is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12;

each R^(y) is independently H, F, Cl, Br, I, —CN, —N₃, —NO₂, —OR,—C(R)₂—O—C(R)₃, —C(═Y¹)R, —C(═Y¹)R¹³, —C(═Y¹)OR, —C(═Y¹)N(R)₂, —N(R)₂,—⁺N(R)₃, —SR, —S(O)R, —S(O)₂R, —S(O)₂R¹³, —S(O)(OR), —S(O)₂(OR),—OC(═Y¹)R, —OC(═Y¹)OR, —OC(═Y¹)(N(R)₂), —SC(═Y¹)R, —SC(═Y¹)OR,—SC(═Y¹)(N(R)₂), —N(R)C(═Y¹)R, —N(R)C(═Y¹)OR, —N(R)C(═Y¹)N(R)₂, —SO₂NR₂,(C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈) alkynyl, (C₆-C₂₀) aryl, (C₃-C₂₀)cycloalkyl, (C₂-C₂₀) heterocyclyl, arylalkyl, or heteroarylalkyl,

-   -   wherein each (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈) alkynyl,        (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl,        arylalkyl, or heteroarylalkyl is optionally substituted with 1-3        R²⁰ groups;    -   or when taken together, two R^(y) on the same carbon atom form a        cycloalkyl ring of 3 to 7 carbon atoms;

each R is independently H, (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈)alkynyl, (C₈-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl, orarylalkyl;

R⁸ is H, (C₁-C₄) alkyl, or (C₁-C₄) substituted alkyl;

each R¹¹ or R¹² is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, (C₄-C₈)cycloalkylalkyl, (C₃-C₂₀)cycloalkyl,(C₂-C₂₀)heterocyclyl, optionally substituted aryl, optionallysubstituted heteroaryl, —C(═O)(C₁-C₈)alkyl, —S(O)_(n)(C₁-C₈)alkyl oraryl(C₁-C₈)alkyl; or R¹¹ and R¹² taken together with a nitrogen to whichthey are both attached form a 3-to 7-membered heterocyclic ring whereinany one carbon atom of said heterocyclic ring can optionally be replacedwith —O—, —S— or —NR^(a)—;

each R¹³ is independently a cycloalkyl or heterocycle optionallysubstituted with 1-3 R or R²⁰ groups;

each R²⁰ is independently, halogen, CN, N₃, N(R)₂, OR, —SR, —S(O)R,—S(O)₂R, —S(O)(OR), —S(O)₂(OR), —C(═Y¹)R, —C(═Y¹)OR, or C(═Y¹)N(R)₂;

wherein each alkyl, alkenyl, alkynyl, aryl or heteroaryl of each of R¹,R², R³, R⁴, R⁵, R⁸, R¹¹ or R¹² is, independently, optionally substitutedwith 1 to 3 halo, hydroxy, CN, N₃, N(R^(a))₂ or OR^(a); and wherein 1 to3 of the non-terminal carbon atoms of each said (C₁-C₈)alkyl may beoptionally replaced with —O—, —S— or —NR^(a)—;

with the following provisos:

a) when R¹, R³, and R⁵ are hydrogen, R² and R⁴ are hydroxy, R⁶ is cyanoand R⁷ and R⁸ are hydrogen, then Base is not uracil or thymine;

b) when R¹ and R⁴ are hydroxy, R², R³, and R⁵ are hydrogen, R⁶ is cyanoand R⁷ and R⁸ are hydrogen, then Base is not uracil or cytosine;

c) when R¹, R², R³, and R⁵ are hydrogen, R⁴ is hydroxy, R⁶ is cyano andR⁷ and R⁸ are hydrogen, then Base is not uracil, cytosine, thymine or5-iodo-uracil;

d) when R¹, R³, and R⁵ are hydrogen, R² and R⁴ are hydroxy, R⁶ isethenyl and R⁷ and R⁸ are hydrogen, then Base is not uracil or cytosine;

e) when R⁵ is other than H, then R⁸ is H;

f) when R¹ is hydroxy, R², R³, R⁵, and R⁸ are hydrogen, R⁶ is cyano, R⁴is hydrogen or benzoyl, and R⁷ is hydrogen or benzoyl, then Base is notcytosine;

g) when R¹ is acetyl or hydroxy, R², R³, R⁵, R⁷, and Ware hydrogen, R⁴is hydroxy or —OC(O)phenyl, then Base is not 2-oxo-4-hydroxypyrimidinyl;

h) when R¹ is acetoxy, R⁴ is benzoyloxy, R⁶ is cyano, R⁷ is benzoyl, andR², R³, R⁵, and R⁸ are hydrogen, then base is not uracil; and

i) at least one of R¹, R², R³, R⁴ and R⁵ is not hydrogen.

It should be noted that in the provisos discussed throughout whenreferring to the Base without specifically stating that it issubstituted, such as uracil or thymine, the proviso only refers to theunsubstituted Base.

In some embodiments, R¹ is H, CN, OR^(a), (C₁-C₄)alkyl, (C₂-C₄)alkenyl,or (C₂-C₄)alkynyl. In some embodiments, R¹ is hydrogen, methyl, orhydroxy.

In some embodiments, R² is H or OR^(a). In some embodiments, R² ishydrogen, methoxy, or hydroxy.

In some embodiments, R¹ and R² taken together with the carbon to whichthey are attached form a 4-membered cycloalkyl ring wherein 1 to 3carbon atoms of said cycloalkyl ring is optionally replaced by O.

In some embodiments, R³, R⁴, and R⁵ are each independently H, ORE, N₃,CN, (C₁-C₄) alkyl, or (C₂-C₄) alkynyl. In some embodiments, R³, R⁴, andR⁵ are each independently H, hydroxy, N₃, or —OC(O)-isopropyl.

In some embodiments, Base is uracil optionally substituted with halogen,such as, by way of example only, fluoro. In other embodiments, Base iscytosine optionally substituted with halogen, such as, by way of exampleonly, fluoro.

In some embodiments, Base is a pyrimidine represented by Formula VI orVII:

or tautomer thereof,

wherein:

each X¹ or X² is independently C—R¹⁰ or N provided that at least one ofX¹ or X² is C—R¹⁰;

each R⁹ is H, halogen, NR¹¹R¹², N(R¹¹)OR¹¹, NR¹¹NR¹¹R¹², N₃, NO, NO₂,OR¹¹ or SR¹¹; and

each R¹⁰ is independently H, halogen, NR¹¹R¹², N(R¹¹)OR¹¹, NR¹¹NR¹¹R¹²,N₃, NO, NO₂, CHO, CN, —CH(═NR¹¹), —CH═NHNR¹¹, —CH═N(OR¹¹), —CH(OR¹¹)₂,—C(═O)NR¹¹R¹², —C(═S)NR¹¹R¹², —C(═O)OR¹¹, R¹¹, OR¹¹ or SR¹¹;

each R¹¹ or R¹² is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, (C₄-C₈)cycloalkylalkyl, (C₃-C₂₀)cycloalkyl,(C₂-C₂₀)heterocyclyl, optionally substituted aryl, optionallysubstituted heteroaryl, —C(═O)(C₁-C₈)alkyl, —S(O)_(n)(C₁-C₈)alkyl oraryl(C₁-C₈)alkyl; or R¹¹ and R¹² taken together with a nitrogen to whichthey are both attached form a 3-to 7-membered heterocyclic ring whereinany one carbon atom of said heterocyclic ring can optionally be replacedwith —O—, —S— or —NR^(a)—; and

R¹⁴ is H, (C₁-C₈)alkyl, or (C₄-C₈)cycloalkylalkyl.

In some embodiments, R⁶ is CN, ethenyl, or ethynyl.

In some embodiments, R⁷ is H or

In some embodiments, R⁷ is H or

wherein W¹ and W² are each, independently, a group of the Formula Ib.

Additional embodiments of R⁷ are described below.

In some embodiments,

-   -   R¹ is H, OH, CN, (C₁-C₄)alkyl, (C₂-C₄)alkenyl, or        (C₂-C₄)alkynyl;

R² is H, OH or O(C₁-C₄)alkyl;

-   -   or R¹ and R² taken together with the carbon to which they are        attached form a 3- to 6-membered cycloalkyl ring wherein 1 to 3        carbon atoms of said cycloalkyl ring is optionally replaced by        O;    -   R³ is H or (C₁-C₄)alkyl;    -   R⁴ is H, OH, O(C₁-C₄)alkyl, or OC(O)—(C₁-C₄)alkyl;    -   R⁵ is H, CN, N₃, (C₁-C₄)alkyl, (C₂-C₄)alkenyl, or        (C₂-C₄)alkynyl;    -   R⁶ is CN, ethenyl, 2-haloethen-1-yl, or (C₂-C₈)alkyn-1-yl; and    -   R⁸ is H or (C₁-C₄)alkyl.

In some embodiments,

-   -   R¹ is H, OH, or (C₁-C₄)alkyl;    -   R² is H, OH or O(C₁-C₄)alkyl;    -   or R¹ and R² taken together with the carbon to which they are        attached form a 4-membered cycloalkyl ring wherein one carbon        atom of said cycloalkyl ring is optionally replaced by O;    -   R³ is H or (C₁-C₄)alkyl;    -   R⁴ is H, OH, O(C₁-C₄)alkyl, or —OC(O)—(C₁-C₄)alkyl;    -   R⁵ is H, N₃, or (C₁-C₄)alkyl;    -   R⁶ is CN, ethenyl, or ethynyl; and    -   R⁸ is H or (C₁-C₄) alkyl.

In some embodiments,

Base is a naturally occurring or modified pyrimidine base;

R¹ is H, OH, CN, (C₁-C₄)alkyl, (C₂-C₄)alkenyl, or (C₂-C₄)alkynyl;

R² is H, OH or O(C₁-C₄)alkyl;

or R¹ and R² taken together with the carbon to which they are attachedform a 3-to 6-membered cycloalkyl ring wherein 1 to 3 carbon atoms ofsaid cycloalkyl ring is optionally replaced by O;

R³ is H or (C₁-C₄)alkyl;

R⁴ is H, OH, O(C₁-C₄)alkyl, or —OC(O)—(C₁-C₄)alkyl;

R⁶ is H, CN, N₃, (C₁-C₄)alkyl, (C₂-C₄)alkenyl, or (C₂-C₄)alkynyl;

R⁶ is CN, ethenyl, 2-haloethen-1-yl, or (C₂-C₈)alkyn-1-yl;

R⁷ is H, —C(═O)R¹¹, —C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹,

S(O)₂R¹¹, —S(O)(OR¹¹), —S(O)₂(OR¹¹), —SO₂NR¹¹R¹², or Formula Ia

Y is O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR²;

W¹ and W², when taken together, are —Y³(C(R^(y))₂)₃Y³—;

or one of W¹ or W² together with either R³ or R⁴ is —Y³— and the otherof W¹ or W² is Formula Ib;

or W¹ and W² are each, independently, a group of the Formula Ib:

wherein:

each Y¹ is independently O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂;

each Y² is independently a bond, O, CR₂, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR),N—NR₂, S, S—S, S(O), or S(O)₂;

each Y³ is independently O, S, or NR;

M2 is 0, 1, or 2;

each R⁸ is independently R^(y) or the formula:

wherein:

each M1a, M1c, and M1d is independently 0 or 1;

M1b is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12;

each R^(y) is independently H, F, Cl, Br, I, OH, R, —C(R)₂—O—C(R)₃,—C(═Y¹)R, —C(═Y¹)R¹³, —C(═Y¹)OR, —C(═Y¹)N(R)₂, —N(R)₂, —⁺N(R)₃, —SR,—S(O)R, —S(O)₂R, —S(O)₂R¹³, —S(O)(OR), —S(O)₂(OR), —OC(═Y¹)R,—OC(═Y¹)OR, —OC(═Y¹)(N(R)₂), —SC(═Y¹)R, —SC(═Y¹)OR, —SC(═Y¹)(N(R)₂),—N(R)C(═Y¹)R, —N(R)C(═Y¹)OR, —N(R)C(═Y¹)N(R)₂, —SO₂NR₂, —CN, —N₃, —NO₂,—OR, (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl,(C₂-C₂₀) heterocycloalkyl, arylalkyl, or heteroarylalkyl,

-   -   wherein each (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈) alkynyl,        (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl,        arylalkyl, or heteroarylalkyl is optionally substituted with 1-3        R²⁰ groups;    -   or when taken together, two R^(y) on the same carbon atom form a        cycloalkyl ring of 3 to 7 carbon atoms;

each R is independently H, (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈)alkynyl, (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl, orarylalkyl;

R⁸ is H, (C₁-C₄) alkyl, or (C₁-C₄) substituted alkyl;

each R¹¹ or R¹² is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, (C₄-C₈)cycloalkylalkyl, optionally substituted aryl,optionally substituted heteroaryl, —C(═O)(C₁-C₈)alkyl,—S(O)_(n)(C₁-C₈)alkyl or aryl(C₁-C₈)alkyl; or R¹¹ and R¹² taken togetherwith a nitrogen to which they are both attached form a 3-to 7-memberedheterocyclic ring wherein any one carbon atom of said heterocyclic ringcan optionally be replaced with —O—, —S— or —NR^(a)—;

wherein each alkyl, alkenyl, alkynyl, aryl or heteroaryl of each R¹, R²,R³, R⁴, R⁵, R⁸, R¹¹ or R¹² is, independently, optionally substitutedwith 1 to 3 halo, hydroxy, CN, N₃, N(R^(a))₂ or OR^(a); and wherein 1 to3 of the non-terminal carbon atoms of each said (C₁-C₈)alkyl may beoptionally replaced with —O—, —S— or —NR^(a)—;

provided that least one of R¹, R², R³, and R⁴ are hydroxy.

In some embodiments, R⁷ is H or

In some embodiments, the group —R⁷—O—C(R⁸)—C(R⁵)—C(R³)(R⁴)— is of thefollowing formula:

In some embodiments, the group —R⁷—O—C(R⁸)—C(R⁵)—C(R³)(R⁴)— is of thefollowing formula:

In some embodiments, the compound is of the following formula:

In some embodiments, the compound is of the following formula:

In some embodiments, at least one of R¹, R², R³, and R⁴ are hydroxy. Insome embodiments, at least two of R¹, R², R³, and R⁴ are hydroxy.

In some embodiments, the compound is represented by Formula II:

wherein each Y and Y¹ is O and each of Base, R¹, R², R³, R⁴, R⁵, R⁷, andR⁸ is as described above.

In some embodiments, the compound is represented by Formula III:

wherein each Y and Y¹ is O and each of Base, R¹, R², R³, R⁴, R⁵, R⁷, andR⁸ is as described above.

In some embodiments, the compound is represented by Formula IV:

wherein each Y and Y¹ is O and each of Base, R¹, R², R³, R⁴, R⁵, R⁷, andR⁸ is as described above.

In some embodiments, the compound is represented by Formula V:

wherein each Y and Y¹ is O and X is halogen and each of Base, R¹, R²,R³, R⁴, R⁵, R⁷, and R⁸ is as described above. In some embodiments,halogen is fluoro, chloro, or iodo. In some embodiments, bromovinylgroups are not included in the R⁶ position.

In another embodiment, the compound of Formula I-V is a compoundselected from the group consisting of:

or a pharmaceutically acceptable salt thereof.

In another embodiment, the compound of Formula I-V is a compoundselected from the group consisting of:

or a pharmaceutically acceptable salt thereof.

In some embodiments, the following compound is not included in thecompounds but may be useful in the methods of the invention:

In another embodiment, provided are pharmaceutical compositionscomprising an effective amount of a Formula I-V compound, or a compoundas described herein, or a pharmaceutically acceptable salt thereof, incombination with a pharmaceutically acceptable diluent or carrier.

In another embodiment, provided are pharmaceutical compositionscomprising a pharmaceutically acceptable diluent or carrier incombination with an effective amount of a compound of Formula I:

or a pharmaceutically acceptable salt thereof;

wherein:

Base is a naturally occurring or modified pyrimidine base;

R¹ is H, CN, OR^(a), (C₁-C₄)alkyl, (C₁-C₄)substituted alkyl,(C₂-C₄)alkenyl, (C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl,(C₂-C₄)substituted alkynyl or S(O)_(n)R^(a);

R² is H, OR^(a), N(R^(a))₂, N₃, CN, NO₂, S(O)_(n)R^(a), (C₁-C₄)alkyl,(C₄-C₆)cycloalkylalkyl, (C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl,(C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl, or (C₂-C₄)substitutedalkynyl;

or R¹ and R² taken together with the carbon to which they are attachedform a 3-to 6-membered cycloalkyl ring wherein 1 to 3 carbon atoms ofsaid cycloalkyl ring is optionally replaced by O or S(O)_(n);

R³, R⁴, and R⁵ are each independently H, OR^(a), N(R^(a))₂, N₃, CN, NO₂,S(O)_(n)R^(a), halogen, (C₁-C₄)alkyl, (C₄-C₈)cycloalkylalkyl,(C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl, (C₂-C₄)substituted alkenyl,(C₂-C₄)alkynyl, or (C₂-C₄)substituted alkynyl;

or any two of R³, R⁴ or R⁵ on adjacent carbon atoms when taken togetherare —O(CO)O— or when taken together with the ring carbon atoms to whichthey are attached to form a double bond;

R⁶ is CN, ethenyl, 2-haloethen-1-yl, or (C₂-C₈)alkyn-1-yl,

each n is independently 0, 1, or 2;

each R^(a) is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, aryl(C₁-C₈)alkyl, (C₄-C₈)cycloalkylalkyl, —C(═O)R¹¹,—C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹, —S(O)₂R¹¹, —S(O)(OR¹¹),—S(O)₂(OR¹¹), or —SO₂NR¹¹R¹²;

R⁷ is H, —C(═O)R¹¹, —C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹,—S(O)₂R¹¹, —S(O)(OR¹¹), —S(O)₂(OR¹¹), —SO₂NR¹¹R¹², or the group ofFormula Ia

wherein

Y is O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂;

W¹ and W², when taken together, are —Y³(C(R^(y))₂)₃Y³—;

or one of W¹ or W² together with either R³ or R⁴ is —Y³— and the otherof W¹ or W² is Formula Ib;

or W¹ and W² are each, independently, a group of Formula Ib:

wherein:

each Y¹ is independently O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂;

each Y² is independently a bond, O, CR₂, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR),N—NR₂, S, S—S, S(O), or S(O)₂;

each Y³ is independently O, S, or NR;

M2 is 0, 1, or 2;

each R⁸ is a group of Formula Ic

wherein:

each M1a, M1c, and M1d is independently 0 or 1;

M1b is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12;

each R^(y) is independently H, F, Cl, Br, I, —CN, —N₃, —NO₂, —OR,—C(R)₂—O—C(R)₃, —C(═Y¹)R, —C(═Y¹)R¹³, —C(═Y¹)OR, —C(═Y¹)N(R)₂, —N(R)₂,—⁺N(R)₃, —SR, —S(O)R, —S(O)₂R, —S(O)₂R¹³, —S(O)(OR), —S(O)₂(OR),—OC(═Y¹)R, —OC(═Y¹)OR, —OC(═Y¹)(N(R)₂), —SC(═Y¹)R, —SC(═Y¹)OR,—SC(═Y¹)(N(R)₂), —N(R)C(═Y¹)R, —N(R)C(═Y¹)OR, —N(R)C(═Y¹)N(R)₂, —SO₂NR₂,(C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈) alkynyl, (C₆-C₂₀) aryl, (C₃-C₂₀)cycloalkyl, (C₂-C₂₀) heterocyclyl, arylalkyl, or heteroarylalkyl,

-   -   wherein each (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈) alkynyl,        (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl,        arylalkyl, or heteroarylalkyl is optionally substituted with 1-3        R²⁰ groups;    -   or when taken together, two R^(y) on the same carbon atom form a        cycloalkyl ring of 3 to 7 carbon atoms;

each R is independently H, (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈)alkynyl, (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl, orarylalkyl;

R⁸ is H, (C₁-C₄) alkyl, or (C₁-C₄) substituted alkyl;

each R¹¹ or R¹² is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, (C₄-C₈)cycloalkylalkyl, (C₃-C₂₀)cycloalkyl,(C₂-C₂₀)heterocyclyl, optionally substituted aryl, optionallysubstituted heteroaryl, —C(═O)(C₁-C₈)alkyl, —S(O)_(n)(C₁-C₈)alkyl oraryl(C₁-C₈)alkyl; or R¹¹ and R¹² taken together with a nitrogen to whichthey are both attached form a 3-to 7-membered heterocyclic ring whereinany one carbon atom of said heterocyclic ring can optionally be replacedwith —O—, —S— or —NR^(a)—;

each R¹³ is independently a cycloalkyl or heterocycle optionallysubstituted with 1-3 R or R²⁰ groups;

each R²⁰ is independently, halogen, CN, N₃, N(R)₂, OR, —SR, —S(O)R,—S(O)₂R, —S(O)(OR), —S(O)₂(OR), —C(═Y¹)R, —C(═Y¹)OR, or C(═Y¹)N(R)₂;

wherein each alkyl, alkenyl, alkynyl, aryl or heteroaryl of each of R¹,R², R³, R⁴, R⁵, R⁸, R¹¹ or R¹² is, independently, optionally substitutedwith 1 to 3 halo, hydroxy, CN, N₃, N(R^(a))₂ or OR^(a); and wherein 1 to3 of the non-terminal carbon atoms of each said (C₁-C₈)alkyl may beoptionally replaced with —O—, —S— or —NR^(a)—

with the proviso that at least one of R¹, R², R³, R⁴ and R⁵ is nothydrogen.

In another embodiment, the pharmaceutical compositions further compriseat least one additional therapeutic agent selected from the groupconsisting of interferons, ribavirin analogs, NS3 protease inhibitors,NS5a inhibitors, NS5b polymerase inhibitors, alpha-glucosidase 1inhibitors, cyclophilin inhibitors, hepatoprotectants, other nucleosideinhibitors of HCV, non-nucleoside inhibitors of HCV, and other drugs fortreating HCV.

In still other embodiments, the pharmaceutical compositions furthercomprise at least one viral neuramidase inhibitor or viral M2 channelinhibitor, such as, by way of example only oseltamivir, zanamivir,laninamivir, peramivir, amantadine and rimantadine.

Additional combination therapies are provided below.

Methods

In another embodiment, is provided a method of inhibiting HCV polymerasecomprising administering to a mammal in need thereof a compound of theinvention.

In another embodiment, the present invention is directed to a method ofinhibiting HCV polymerase comprising administering to a mammal in needthereof a therapeutically effective amount of a compound of Formula I:

or a pharmaceutically acceptable salt thereof;

wherein:

Base is a naturally occurring or modified pyrimidine base;

R¹ is H, CN, OR^(a), (C₁-C₄)alkyl, (C₁-C₄)substituted alkyl,(C₂-C₄)alkenyl, (C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl,(C₂-C₄)substituted alkynyl or S(O)_(n)R^(a);

R² is H, OR^(a), N(R^(a))₂, N₃, CN, NO₂, S(O)_(n)R^(a), (C₁-C₄)alkyl,(C₄-C₆)cycloalkylalkyl, (C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl,(C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl, or (C₂-C₄)substitutedalkynyl;

or R¹ and R² taken together with the carbon to which they are attachedform a 3-to 6-membered cycloalkyl ring wherein 1 to 3 carbon atoms ofsaid cycloalkyl ring is optionally replaced by O or S(O)_(n);

R³, R⁴, and R⁵ are each independently H, OR^(a), N(R^(a))₂, N₃, CN, NO₂,S(O)_(n)R^(a), halogen, (C₁-C₄)alkyl, (C₄-C₈)cycloalkylalkyl,(C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl, (C₂-C₄)substituted alkenyl,(C₂-C₄)alkynyl, or (C₂-C₄)substituted alkynyl;

or any two of R³, R⁴ or R⁵ on adjacent carbon atoms when taken togetherare —O(CO)O— or when taken together with the ring carbon atoms to whichthey are attached to form a double bond;

R⁶ is CN, ethenyl, 2-haloethen-1-yl, or (C₂-C₈)alkyn-1-yl,

each n is independently 0, 1, or 2;

each R^(a) is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, aryl(C₁-C₈)alkyl, (C₄-C₈)cycloalkylalkyl, —C(═O)R¹¹,—C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹, —S(O)₂R¹¹, —S(O)(OR¹¹),—S(O)₂(OR¹¹), or —SO₂NR¹¹R¹²;

R⁷ is H, —C(═O)R¹¹, —C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹,—S(O)₂R¹¹, —S(O)(OR¹¹), —S(O)₂(OR¹¹), —SO₂NR¹¹R¹², or the group ofFormula Ia

wherein

Y is O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂;

W¹ and W², when taken together, are —Y³(C(R^(y))₂)₃Y³—;

or one of W¹ or W² together with either R³ or R⁴ is —Y³— and the otherof W¹ or W² is Formula Ib;

or W¹ and W² are each, independently, a group of Formula Ib:

wherein:

each Y¹ is independently O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂;

each Y² is independently a bond, O, CR₂, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR),N—NR₂, S, S—S, S(O), or S(O)₂;

each Y³ is independently O, S, or NR;

M2 is 0, 1, or 2;

each R^(x) is a group of Formula Ic

wherein:

each M1a, M1c, and M1d is independently 0 or 1;

M1b is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12;

each R^(y) is independently H, F, Cl, Br, I, —CN, —N₃, —NO₂, —OR,—C(R)₂—O—C(R)₃, —C(═Y¹)R, —C(═Y¹)R¹³, —C(═Y¹)OR, —C(═Y¹)N(R)₂, —N(R)₂,—⁺N(R)₃, —SR, —S(O)R, —S(O)₂R, —S(O)₂R¹³, —S(O)(OR), —S(O)₂(OR),—OC(═Y¹)R, —OC(═Y¹)OR, —OC(═Y¹)(N(R)₂), —SC(═Y¹)R, —SC(═Y¹)OR,—SC(═Y¹)(N(R)₂), —N(R)C(═Y¹)R, —N(R)C(═Y¹)OR, —N(R)C(═Y¹)N(R)₂, —SO₂NR₂,(C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈) alkynyl, C₆-C₂₀ aryl, C₃-C₂₀cycloalkyl, C₂-C₂₀ heterocyclyl, arylalkyl, or heteroarylalkyl,

-   -   wherein each (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈) alkynyl,        (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl,        arylalkyl, or heteroarylalkyl is optionally substituted with 1-3        R²⁰ groups;    -   or when taken together, two R^(y) on the same carbon atom form a        cycloalkyl ring of 3 to 7 carbon atoms;

each R is independently H, (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈)alkynyl, C₆-C₂₀ aryl, C₃-C₂₀ cycloalkyl, C₂-C₂₀ heterocyclyl, orarylalkyl;

R⁸ is H, (C₁-C₄) alkyl, or (C₁-C₄) substituted alkyl;

each R¹¹ or R¹² is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, (C₄-C₈)cycloalkylalkyl, (C₃-C₂₀)cycloalkyl,(C₂-C₂₀)heterocyclyl, optionally substituted aryl, optionallysubstituted heteroaryl, —C(═O)(C₁-C₈)alkyl, —S(O)_(o)(C₁-C₈)alkyl oraryl(C₁-C₈)alkyl; or R¹¹ and R¹² taken together with a nitrogen to whichthey are both attached form a 3- to 7-membered heterocyclic ring whereinany one carbon atom of said heterocyclic ring can optionally be replacedwith —O—, —S— or —NR^(a)—;

each R¹³ is independently a cycloalkyl or heterocycle optionallysubstituted with 1-3 R or R²⁰ groups;

each R²⁰ is independently, halogen, CN, N₃, N(R)₂, OR, —SR, —S(O)R,—S(O)₂R, —S(O)(OR), —S(O)₂(OR), —C(═Y¹)R, —C(═Y¹)OR, or C(═Y¹)N(R)₂;

wherein each alkyl, alkenyl, alkynyl, aryl or heteroaryl of each of R¹,R², R³, R⁴, R⁵, R⁸, R¹¹ or R¹² is, independently, optionally substitutedwith 1 to 3 halo, hydroxy, CN, N₃, N(R^(a))₂ or OR^(a); and wherein 1 to3 of the non-terminal carbon atoms of each said (C₁-C₈)alkyl may beoptionally replaced with —O—, —S— or —NR^(a)—;

with the proviso that at least one of R¹, R², R³, R⁴ and R⁵ is nothydrogen.

In one embodiment, the invention is directed to a method of treating aviral infection caused by a Flaviviridae virus comprising administeringto a mammal in need thereof a therapeutically effective amount of acompound or pharmaceutical composition as described above. In someembodiments, the virus is selected from the group consisting of denguevirus, yellow fever virus, West Nile virus, Japanese encephalitis virus,tick-borne encephalitis virus, Kunjin virus, Murray Valley encephalitisvirus, St. Louis encephalitis virus, Omsk hemorrhagic fever virus,bovine viral diarrhea virus, Zika virus and Hepatitis C virus. In oneembodiment, the viral infection is caused by Hepatitis C virus.

In methods of the invention, the method further comprises administeringat least one additional therapeutic agent selected from the groupconsisting of interferons, ribavirin analogs, NS3 protease inhibitors,NS5b polymerase inhibitors, NS5a inhibitors, alpha-glucosidase 1inhibitors, cyclophilin inhibitors, hepatoprotectants, other nucleosideinhibitors of HCV, non-nucleoside inhibitors of HCV, and other drugs fortreating HCV.

In another embodiment, the invention is directed to a method of treatinga viral infection caused by a Paramyxoviridae virus comprisingadministering to a mammal in need thereof a therapeutically effectiveamount of a compound or pharmaceutical composition as described above.In one embodiment, the virus is a respiratory syncytial virus.

In another embodiment, the invention is directed to a method of treatinga viral infection caused by an Orthomyxoviridae virus comprisingadministering to a mammal in need thereof a therapeutically effectiveamount of a compound or pharmaceutical composition as described above.In some embodiments, the virus is an Influenzavirus A, Influenzavirus Bor Influenzavirus C. In some embodiments, the method further comprisesadministering at least one additional therapeutic agent selected fromthe group consisting of oseltamivir, zanamivir, laninamivir, peramivir,amantadine and rimantadine.

In still other embodiments, the invention is directed to a method oftreating a viral infection caused by a Picornaviridae virus comprisingadministering to a mammal in need thereof a therapeutically effectiveamount of a compound or pharmaceutical composition as described above.In some methods, the virus is an Enterovirus. In some methods, anadditional agent, such as pleconaril and/or BTA-798 are administered.

DEFINITIONS

Unless stated otherwise, the following terms and phrases as used hereinare intended to have the following meanings:

When trade names are used herein, applicants intend to independentlyinclude the trade name product and the active pharmaceuticalingredient(s) of the trade name product.

As used herein, “a compound,” “a compound of the invention,” or “acompound of Formula I” means a compound of Formula I or apharmaceutically acceptable salt, thereof. Similarly, with respect toisolatable intermediates, the phrase “a compound of Formula (number)”means a compound of that formula and pharmaceutically acceptable salts,thereof.

“Alkyl” is hydrocarbon containing normal, secondary, tertiary or cycliccarbon atoms. For example, an alkyl group can have 1 to 20 carbon atoms(i.e., C₁-C₂₀ alkyl), 1 to 8 carbon atoms (i.e., C₁-C₈ alkyl), 1 to 6carbon atoms (i.e., C₁-C₆ alkyl) or 1 to 4 carbon atoms (i.e., C₁-C₄alkyl). Examples of suitable alkyl groups include, but are not limitedto, methyl (Me, —CH₃), ethyl (Et, —CH₂CH₃), 1-propyl (n-Pr, n-propyl,—CH₂CH₂CH₃), 2-propyl (i-Pr, i-propyl, —CH(CH₃)₂), 1-butyl (n-Bu,n-butyl, —CH₂CH₂CH₂CH₃), 2-methyl-1-propyl (1-Bu, i-butyl,—CH₂CH(CH₃)₂), 2-butyl (s-Bu, s-butyl, —CH(CH₃)CH₂CH₃),2-methyl-2-propyl (t-Bu, t-butyl, —C(CH₃)₃), 1-pentyl (n-pentyl,—CH₂CH₂CH₂CH₂CH₃), 2-pentyl (—CH(CH₃)CH₂CH₂CH₃), 3-pentyl(—CH(CH₂CH₃)₂), 2-methyl-2-butyl (—C(CH₃)₂CH₂CH₃), 3-methyl-2-butyl(—CH(CH₃)CH(CH₃)₂), 3-methyl-1-butyl (—CH₂CH₂CH(CH₃)₂), 2-methyl-1-butyl(—CH₂CH(CH₃)CH₂CH₃), 1-hexyl (—CH₂CH₂CH₂CH₂CH₂CH₃), 2-hexyl(—CH(CH₃)CH₂CH₂CH₂CH₃), 3-hexyl (—CH(CH₂CH₃)(CH₂CH₂CH₃)),2-methyl-2-pentyl (—C(CH₃)₂CH₂CH₂CH₃), 3-methyl-2-pentyl(—CH(CH₃)CH(CH₃)CH₂CH₃), 4-methyl-2-pentyl (—CH(CH₃)CH₂CH(CH₃)₂),3-methyl-3-pentyl (—C(CH₃)(CH₂CH₃)₂), 2-methyl-3-pentyl(—CH(CH₂CH₃)CH(CH₃)₂), 2,3-dimethyl-2-butyl (—C(CH₃)₂CH(CH₃)₂),3,3-dimethyl-2-butyl (—CH(CH₃)C(CH₃)₃, and octyl (—(CH₂)₇CH₃).

“Alkoxy” means a group having the formula —O-alkyl, in which an alkylgroup, as defined above, is attached to the parent molecule via anoxygen atom. The alkyl portion of an alkoxy group can have 1 to 20carbon atoms (i.e., C₁-C₂₀ alkoxy), 1 to 12 carbon atoms (i.e., C₁-C₁₂alkoxy), or 1 to 6 carbon atoms (i.e., C₁-C₆ alkoxy). Examples ofsuitable alkoxy groups include, but are not limited to, methoxy (—O—CH₃or —OMe), ethoxy (—OCH₂CH₃ or —OEt), t-butoxy (—O—C(CH₃)₃ or —OtBu) andthe like.

“Haloalkyl” is an alkyl group, as defined above, in which one or morehydrogen atoms of the alkyl group is replaced with a halogen atom. Thealkyl portion of a haloalkyl group can have 1 to 20 carbon atoms (i.e.,C₁-C₂₀ haloalkyl), 1 to 12 carbon atoms (i.e., C₁-C₁₂ haloalkyl), or 1to 6 carbon atoms (i.e., C₁-C₆ alkyl). Examples of suitable haloalkylgroups include, but are not limited to, —CF₃, —CHF₂, —CFH₂, —CH₂CF₃, andthe like.

“Alkenyl” is a hydrocarbon containing normal, secondary, tertiary orcyclic carbon atoms with at least one site of unsaturation, i.e., acarbon-carbon, sp² double bond. For example, an alkenyl group can have 2to 20 carbon atoms (i.e., C₂-C₂₀ alkenyl), 2 to 8 carbon atoms (i.e.,C₂-C₈ alkenyl), 2 to 6 carbon atoms (i.e., C₂-C₆ alkenyl) or 2 to 4carbon atoms (i.e., C₂-C₄ alkenyl). Examples of suitable alkenyl groupsinclude, but are not limited to, ethenyl or vinyl (both having astructure —CH═CH₂), allyl (—CH₂CH═CH₂), cyclopentenyl (—C₅H₇), and5-hexenyl (—CH₂CH₂CH₂CH₂CH═CH₂).

“Alkynyl” is a hydrocarbon containing normal, secondary, tertiary orcyclic carbon atoms with at least one site of unsaturation, i.e., acarbon-carbon, sp triple bond. For example, an alkynyl group can have 2to 20 carbon atoms (i.e., C₂-C₂₀ alkynyl), 2 to 8 carbon atoms (i.e.,C₂-C₈ alkyne,), 2 to 6 carbon atoms (i.e., C₂-C₆ alkynyl), or 2 to 4carbon atoms (i.e., C₂-C₄ alkynyl). Examples of suitable alkynyl groupsinclude, but are not limited to, ethynyl or acetylenic (—C≡CH),propargyl (—CH₂C—═CH), and the like.

“Alkylene” refers to a saturated, branched or straight chain or cyclichydrocarbon radical having two monovalent radical centers derived by theremoval of two hydrogen atoms from the same or two different carbonatoms of a parent alkane. For example, an alkylene group can have 1 to20 carbon atoms, 1 to 10 carbon atoms, or 1 to 6 carbon atoms. Typicalalkylene radicals include, but are not limited to, methylene (—CH₂—),1,1-ethyl (—CH(CH₃)—), 1,2-ethyl (—CH₂CH₂—), 1,1-propyl (—CH(CH₂CH₃)—),1,2-propyl (—CH₂CH(CH₃)—), 1,3-propyl (—CH₂CH₂CH₂—), 1,4-butyl(—CH₂CH₂CH₂CH₂—), and the like.

“Alkenylene” refers to an unsaturated, branched or straight chain orcyclic hydrocarbon radical having two monovalent radical centers derivedby the removal of two hydrogen atoms from the same or two differentcarbon atoms of a parent alkene. For example, and alkenylene group canhave 1 to 20 carbon atoms, 1 to 10 carbon atoms, or 1 to 6 carbon atoms.Typical alkenylene radicals include, but are not limited to,1,2-ethylene (—CH═CH—).

“Alkynylene” refers to an unsaturated, branched or straight chain orcyclic hydrocarbon radical having two monovalent radical centers derivedby the removal of two hydrogen atoms from the same or two differentcarbon atoms of a parent alkyne. For example, an alkynylene group canhave 1 to 20 carbon atoms, 1 to 10 carbon atoms, or 1 to 6 carbon atoms.Typical alkynylene radicals include, but are not limited to, acetylene(—C≡C—), propargyl (—CH₂C≡C—), and 4-pentynyl (—CH₂CH₂CH₂C≡C—).

“Amino” refers generally to a nitrogen radical which can be considered aderivative of ammonia, having the formula —N(X)₂, where each “X” isindependently H, substituted or unsubstituted alkyl, substituted orunsubstituted carbocyclyl, substituted or unsubstituted heterocyclyl,etc. The hybridization of the nitrogen is approximately sp³. Nonlimitingtypes of amino include —NH₂, —N(alkyl)₂, —NH(alkyl), —N(carbocyclyl)₂,—NH(carbocyclyl), —N(heterocyclyl)₂, —NH(heterocyclyl), —N(aryl)₂,—NH(aryl), —N(alkyl)(aryl), —N(alkyl)(heterocyclyl),—N(carbocyclyl)(heterocyclyl), —N(aryl)(heteroaryl),—N(alkyl)(heteroaryl), etc. The term “alkylamino” refers to an aminogroup substituted with at least one alkyl group. Nonlimiting examples ofamino groups include —NH₂, —NH(CH₃), —N(CH₃)₂, —NH(CH₂CH₃), —N(CH₂CH₃)₂,—NH(phenyl), —N(phenyl)₂, —NH(benzyl), —N(benzyl)₂, etc. Substitutedalkylamino refers generally to alkylamino groups, as defined above, inwhich at least one substituted alkyl, as defined herein, is attached tothe amino nitrogen atom. Non-limiting examples of substituted alkylaminoincludes —NH(alkylene-C(O)—OH), —NH(alkylene-C(O)—O-alkyl),—N(alkylene-C(O)—OH)₂, —N(alkylene-C(O)—O-alkyl)₂, etc.

“Carbocycle” or “carbocyclyl” refers to a saturated (i.e.,“cycloalkyl”), partially unsaturated (e.g.; “cycloalkenyl,”cycloalkadienyl, etc.) or aromatic ring (i.e., “aryl”) having 3 to 7carbon atoms as a monocycle, 7 to 12 carbon atoms as a bicycle, and upto about 20 carbon atoms as a polycycle. Monocyclic carbocycles have 3to 7 ring atoms, still more typically 5 or 6 ring atoms. In certainembodiments, cycloalkyl groups can have 3 to 6 carbon atoms, or 5 or 6carbon atoms. Bicyclic carbocycles have 7 to 12 ring atoms, e.g.,arranged as a bicyclo [4,5], [5,5], [5,6] or [6,6] system, or 9 or 10ring atoms arranged as a bicyclo [5,6] or [6,6] system, or spiro-fusedrings. Non-limiting examples of monocyclic carbocycles includecyclopropyl, cyclobutyl, cyclopentyl, 1-cyclopent-1-enyl,1-cyclopent-2-enyl, 1-cyclopent-3-enyl, cyclohexyl, 1-cyclohex-1-enyl,1-cyclohex-2-enyl, 1-cyclohex-3-enyl, and phenyl. Non-limiting examplesof bicyclo carbocycles includes naphthyl, tetrahydronapthalene, anddecaline.

“Cycloalkylalkyl” or “carbocyclylalkyl” or “cycloalkylalkylene” refersto an acyclic alkyl radical in which one of the hydrogen atoms bonded toa carbon atom is replaced with a cycloalkyl or carbocyclyl radical asdescribed herein. Typical, but non-limiting, examples of cycloalkylalkylgroups include cyclopropylmethyl, cyclopropylethyl, cyclobutylmethyl,cyclopentylmethyl and cyclohexylmethyl. In cycloalkyl-alkylene groups,typically comprises 4 to 20 (i.e., C₄ to C₂₀) carbon atoms, e.g., thealkyl portion of the group is 1 to 6 (i.e., C₁ to C₆) carbon atoms andthe cycloalkyl moiety is 3 to 14 carbon atoms.

“Aryl” means an aromatic hydrocarbon radical derived by the removal ofone hydrogen atom from a single carbon atom of a parent aromatic ringsystem. For example, an aryl group can have 6 to 20 carbon atoms, 6 to14 carbon atoms, or 6 to 10 carbon atoms. Typical aryl groups include,but are not limited to, radicals derived from benzene (e.g., phenyl),substituted benzene, naphthalene, anthracene, biphenyl, and the like.

“Arylalkyl” refers to an acyclic alkyl radical in which one of thehydrogen atoms bonded to a carbon atom, typically a terminal or sp³carbon atom, is replaced with an aryl radical. Typical arylalkyl groupsinclude, but are not limited to, benzyl, 2-phenylethan-1-yl,naphthylmethyl, 2-naphthylethan-1-yl, naphthobenzyl,2-naphthophenylethan-1-yl and the like. The arylalkyl group can comprise7 to 20 carbon atoms, e.g., the alkyl moiety is 1 to 6 carbon atoms andthe aryl moiety is 6 to 14 carbon atoms.

The term “substituted” in reference to alkyl, alkylene, aryl, arylalkyl,alkoxy, heterocyclyl, heteroaryl, carbocyclyl, etc., for example,“substituted alkyl”, “substituted alkylene”, “substituted aryl”,“substituted arylalkyl”, “substituted heterocyclyl”, and “substitutedcarbocyclyl” means alkyl, alkylene, aryl, arylalkyl, heterocyclyl,carbocyclyl respectively, in which one or more hydrogen atoms are eachindependently replaced with a non-hydrogen substituent. Typicalsubstituents include, but are not limited to, —X¹, —R^(b), —O⁻, ═O,—OR^(b), —SR^(b), —S⁻, —NR^(b) ₂, —N⁺R^(b) ₃, ═NR^(b), —CX₃, —CN, —OCN,—SCN, —N═C═O, —NCS, —NO, —NO₂, ═N₂, —N₃, —NHC(═O)R^(b), —OC(═O)R^(b),—NHC(═O)NR^(b) ₂, —S(═O)₂—, —S(═O)₂OH, —S(═O)₂R^(b), —OS(═O)₂OR^(b),—S(═O)₂NR^(b) ₂, —S(═O)R^(b), —OP(═O)(OR^(b))₂, —P(═O)(OR^(b))₂,—P(═O)(O⁻)₂, —P(═O)(OH)₂, —P(O)(OR^(b))(O⁻), —C(═O)R^(b), —C(═O)X,—C(S)R^(b), —C(O)OR^(b), —C(O)O⁻, —C(S)OR^(b), —C(O)SR^(b), —C(S)SR^(b),—C(O)NR^(b) ₂, —C(S)NR^(b) ₂, —C(═NR^(b))NR^(b) ₂, where each X¹ isindependently a halogen: F, Cl, Br, or I; and each R^(b) isindependently H, alkyl, aryl, arylalkyl, a heterocycle, or a protectinggroup or prodrug moiety. Alkylene, alkenylene, and alkynylene groups mayalso be similarly substituted. Unless otherwise indicated, when the term“substituted” is used in conjunction with groups such as arylalkyl,which have two or more moieties capable of substitution, thesubstituents can be attached to the aryl moiety, the alkyl moiety, orboth.

The term “prodrug” as used herein refers to any compound that whenadministered to a biological system generates the drug substance, i.e.,active ingredient, as a result of spontaneous chemical reaction(s),enzyme catalyzed chemical reaction(s), photolysis, and/or metabolicchemical reaction(s). A prodrug is thus a covalently modified analog orlatent form of a therapeutically active compound.

“Heterocycle” or “heterocyclyl” as used herein includes by way ofexample and not limitation those heterocycles described in Paquette, LeoA.; Principles of Modern Heterocyclic Chemistry (W. A. Benjamin, NewYork, 1968), particularly Chapters 1, 3, 4, 6, 7, and 9; The Chemistryof Heterocyclic Compounds, A Series of Monographs” (John Wiley & Sons,New York, 1950 to present), in particular Volumes 13, 14, 16, 19, and28; and J. Am. Chem. Soc. (1960) 82:5566. In one specific embodiment ofthe invention “heterocycle” includes a “carbocycle” as defined herein,wherein one or more (e.g., 1, 2, 3, or 4) carbon atoms have beenreplaced with a heteroatom (e.g., O, N, or S). The terms “heterocycle”or “heterocyclyl” includes saturated rings, partially unsaturated rings,and aromatic rings (i.e., heteroaromatic rings). Substitutedheterocyclyls include, for example, heterocyclic rings substituted withany of the substituents disclosed herein including carbonyl groups. Anon-limiting example of a carbonyl substituted heterocyclyl is:

Examples of heterocycles include by way of example and not limitationpyridyl, dihydroypyridyl, tetrahydropyridyl (piperidyl), thiazolyl,tetrahydrothiophenyl, sulfur oxidized tetrahydrothiophenyl, pyrimidinyl,furanyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, tetrazolyl,benzofuranyl, thianaphthalenyl, indolyl, indolenyl, quinolinyl,isoquinolinyl, benzimidazolyl, piperidinyl, 4-piperidonyl, pyrrolidinyl,2-pyrrolidonyl, pyrrolinyl, tetrahydrofuranyl, tetrahydroquinolinyl,tetrahydroisoquinolinyl, decahydroquinolinyl, octahydroisoquinolinyl,azocinyl, triazinyl, 6H-1,2,5-thiadiazinyl, 2H,6H-1,5,2-dithiazinyl,thienyl, thianthrenyl, pyranyl, isobenzofuranyl, chromenyl, xanthenyl,phenoxathinyl, 2H-pyrrolyl, isothiazolyl, isoxazolyl, pyrazinyl,pyridazinyl, indolizinyl, isoindolyl, 3H-indolyl, 1H-indazoly, purinyl,4H-quinolizinyl, phthalazinyl, naphthyridinyl, quinoxalinyl,quinazolinyl, cinnolinyl, pteridinyl, 4aH-carbazolyl, carbazolyl,β-carbolinyl, phenanthridinyl, acridinyl, pyrimidinyl, phenanthrolinyl,phenazinyl, phenothiazinyl, furazanyl, phenoxazinyl, isochromanyl,chromanyl, imidazolidinyl, imidazolinyl, pyrazolidinyl, pyrazolinyl,piperazinyl, indolinyl, isoindolinyl, quinuclidinyl, morpholinyl,oxazolidinyl, benzotriazolyl, benzisoxazolyl, oxindolyl, benzoxazolinyl,isatinoyl, and bis-tetrahydrofuranyl:

By way of example and not limitation, carbon bonded heterocycles arebonded at position 2, 3, 4, 5, or 6 of a pyridine, position 3, 4, 5, or6 of a pyridazine, position 2, 4, 5, or 6 of a pyrimidine, position 2,3, 5, or 6 of a pyrazine, position 2, 3, 4, or 5 of a furan,tetrahydrofuran, thiofuran, thiophene, pyrrole or tetrahydropyrrole,position 2, 4, or 5 of an oxazole, imidazole or thiazole, position 3, 4,or 5 of an isoxazole, pyrazole, or isothiazole, position 2 or 3 of anaziridine, position 2, 3, or 4 of an azetidine, position 2, 3, 4, 5, 6,7, or 8 of a quinoline or position 1, 3, 4, 5, 6, 7, or 8 of anisoquinoline. Still more typically, carbon bonded heterocycles include2-pyridyl, 3-pyridyl, 4-pyridyl, 5-pyridyl, 6-pyridyl, 3-pyridazinyl,4-pyridazinyl, 5-pyridazinyl, 6-pyridazinyl, 2-pyrimidinyl,4-pyrimidinyl, 5-pyrimidinyl, 6-pyrimidinyl, 2-pyrazinyl, 3-pyrazinyl,5-pyrazinyl, 6-pyrazinyl, 2-thiazolyl, 4-thiazolyl, or 5-thiazolyl.

By way of example and not limitation, nitrogen bonded heterocycles arebonded at position 1 of an aziridine, azetidine, pyrrole, pyrrolidine,2-pyrroline, 3-pyrroline, imidazole, imidazolidine, 2-imidazoline,3-imidazoline, pyrazole, pyrazoline, 2-pyrazoline, 3-pyrazoline,piperidine, piperazine, indole, indoline, 1H-indazole, position 2 of aisoindole, or isoindoline, position 4 of a morpholine, and position 9 ofa carbazole, or 13-carboline. Still more typically, nitrogen bondedheterocycles include 1-aziridyl, 1-azetedyl, 1-pyrrolyl, 1-imidazolyl,1-pyrazolyl, and 1-piperidinyl.

“Heterocyclylalkyl” or “heterocyclylalkylene” refers to an acyclic alkylradical in which one of the hydrogen atoms bonded to a carbon atom,typically a terminal or sp^(a) carbon atom, is replaced with aheterocyclyl radical (i.e., a heterocyclyl-alkylene-moiety). Typicalheterocyclyl alkyl groups include, but are not limited toheterocyclyl-CH₂—, 2-(heterocyclyl)ethan-1-yl, and the like, wherein the“heterocyclyl” portion includes any of the heterocyclyl groups describedabove, including those described in Principles of Modern HeterocyclicChemistry. One skilled in the art will also understand that theheterocyclyl group can be attached to the alkyl portion of theheterocyclyl alkyl by means of a carbon-carbon bond or acarbon-heteroatom bond, with the proviso that the resulting group ischemically stable. The heterocyclyl alkyl group comprises 3 to 20 (i.e.,C₃ to C₂₀) carbon atoms, e.g., the alkyl portion of the group is 1 to 6(i.e., C₁ to C₆) carbon atoms and the heterocyclyl moiety is 2 to 14carbon atoms. Examples of heterocyclylalkyls include by way of exampleand not limitation 5-membered sulfur, oxygen, and/or nitrogen containingheterocycles such as thiazolylmethyl, 2-thiazolylethan-1-yl,imidazolylmethyl, oxazolylmethyl, thiadiazolylmethyl, etc., 6-memberedsulfur, oxygen, and/or nitrogen containing heterocycles such aspiperidinylmethyl, piperazinylmethyl, morpholinylmethyl,pyridinylmethyl, pyridizylmethyl, pyrimidylmethyl, pyrazinylmethyl, etc.

“Heteroaryl” refers to an aromatic heterocyclyl having at least oneheteroatom in the ring. Non-limiting examples of suitable heteroatomswhich can be included in the aromatic ring include oxygen, sulfur, andnitrogen. Non-limiting examples of heteroaryl rings include all of thosearomatic rings listed in the definition of “heterocyclyl”, includingpyridinyl, pyrrolyl, oxazolyl, indolyl, isoindolyl, purinyl, furanyl,thienyl, benzofuranyl, benzothiophenyl, carbazolyl, imidazolyl,thiazolyl, isoxazolyl, pyrazolyl, isothiazolyl, quinolyl, isoquinolyl,pyridazyl, pyrimidyl, pyrazyl, etc.

“Heteroarylalkyl” refers to an alkyl group, as defined herein, in whicha hydrogen atom has been replaced with a heteroaryl group as definedherein. Non-limiting examples of heteroaryl alkyl include—CH₂-pyridinyl, —CH₂-pyrrolyl, —CH₂-oxazolyl, —CH₂-indolyl,—CH₂-isoindolyl, —CH₂-purinyl, —CH₂-furanyl, —CH₂-thienyl,—CH₂-benzofuranyl, —CH₂-benzothiophenyl, —CH₂-carbazolyl,—CH₂-imidazolyl, —CH₂-thiazolyl, —CH₂-isoxazolyl, —CH₂-pyrazolyl,—CH₂-isothiazolyl, —CH₂-quinolyl, —CH₂-isoquinolyl, —CH₂-pyridazyl,—CH₂-pyrimidyl, —CH₂-pyrazyl, —CH(CH₃)-pyridinyl, —CH(CH₃)-pyrrolyl,—CH(CH₃)-oxazolyl, —CH(CH₃)-indolyl, —CH(CH₃)-isoindolyl,—CH(CH₃)-purinyl, —CH(CH₃)-furanyl, —CH(CH₃)-thienyl,—CH(CH₃)-benzofuranyl, —CH(CH₃)-benzothiophenyl, —CH(CH₃)-carbazolyl,—CH(CH₃)-imidazolyl, —CH(CH₃)-thiazolyl, —CH(CH₃)-isoxazolyl,—CH(CH₃)-pyrazolyl, —CH(CH₃)-isothiazolyl, —CH(CH₃)-quinolyl,—CH(CH₃)-isoquinolyl, —CH(CH₃)-pyridazyl, —CH(CH₃)-pyrimidyl,—CH(CH₃)-pyrazyl, etc.

The term “optionally substituted” in reference to a particular moiety ofthe compound of Formula I-V (e.g., an optionally substituted aryl group)refers to a moiety wherein all substituents are hydrogen or wherein oneor more of the hydrogens of the moiety may be replaced by substituentssuch as those listed under the definition of “substituted”.

The term “optionally replaced” in reference to a particular moiety ofthe compound of Formula I-V (e.g., the carbon atoms of said (C₁-C₈)alkylmay be optionally replaced by —S—, or —NR^(a)—) means that one or moreof the methylene groups of the (C₁-C₈)alkyl may be replaced by 0, 1, 2,or more of the groups specified (e.g., —O—, —S—, or —NR^(a)—).

The term “non-terminal carbon atom(s)” in reference to an alkyl,alkenyl, alkynyl, alkylene, alkenylene, or alkynylene moiety refers tothe carbon atoms in the moiety that intervene between the first carbonatom of the moiety and the last carbon atom in the moiety. Therefore, byway of example and not limitation, in the alkyl moiety—CH₂(C*)H₂(C*)H₂CH₃ or alkylene moiety —CH₂(C*)H₂(C*)H₂CH₂— the C* atomswould be considered to be the non-terminal carbon atoms.

Certain Y and Y¹ alternatives are nitrogen oxides such as ⁺N(O)(R) or⁺N(O)(OR). These nitrogen oxides, as shown here attached to a carbonatom, can also be

represented by charge separated groups such as respectively, and areintended to be equivalent to the aforementioned representations for thepurposes of describing this invention.

The term “pyrimidine” base comprises, but is not limited to naturallyoccurring or modified pyrimidine bases, such as thymine, cytosine,5-fluorocytosine, 5-methylcytosine, 6-azapyrimidine, including6-azacytosine, 2- and/or 4-mercaptopyrmidine, uracil, 5-halouracil,including 5-fluorouracil, C⁵-alkylpyrimidines, C⁵-benzylpyrimidines,C⁵-halopyrimidines, C⁵-vinylpyrimidine, C⁵-acetylenic pyrimidine,C⁵-acyl pyrimidine, C⁵-amidopyrimidine, C⁵-cyanopyrimidine,C⁵-5-iodopyrimidine, C⁶-iodo-pyrimidine, C⁵—Br-vinyl pyrimidine,C⁶—Br-vinyl pyrimidine, C⁵-nitropyrimidine, C⁵-amino-pyrimidine,5-azacytidinyl, and 5-azauracilyl. Tautomers of these bases are alsoincluded in the scope of the invention. For example, uracil tautomershave the following structures:

The pyrimidine bases of Formula I-V are linked to the ribose sugar, oranalog thereof, through a nitrogen atom of the base. Functional oxygenand nitrogen groups on the base can be protected as necessary ordesired. Suitable protecting groups are well known to those skilled inthe art, and include trimethylsilyl, dimethylhexylsilyl,t-butyldimethylsilyl, and t-butyldiphenylsilyl, trityl, alkyl groups,and acyl groups such as acetyl and propionyl, methanesulfonyl, andp-toluenesulfonyl.

Unless otherwise specified, the carbon atoms of the compounds of FormulaI-V are intended to have a valence of four. In some chemical structurerepresentations where carbon atoms do not have a sufficient number ofvariables attached to produce a valence of four, the remaining carbonsubstituents needed to provide a valence of four should be assumed to behydrogen. For example,

has the same meaning as

“Protecting group” refers to a moiety of a compound that masks or altersthe properties of a functional group or the properties of the compoundas a whole. The chemical substructure of a protecting group varieswidely. One function of a protecting group is to serve as anintermediate in the synthesis of the parental drug substance. Chemicalprotecting groups and strategies for protection/deprotection are wellknown in the art. See: “Protective Groups in Organic Chemistry”,Theodora W. Greene (John Wiley & Sons, Inc., New York, 1991. Protectinggroups are often utilized to mask the reactivity of certain functionalgroups, to assist in the efficiency of desired chemical reactions, e.g.,making and breaking chemical bonds in an ordered and planned fashion.Protection of functional groups of a compound alters other physicalproperties besides the reactivity of the protected functional group,such as the polarity, lipophilicity (hydrophobicity), and otherproperties which can be measured by common analytical tools. Chemicallyprotected intermediates may themselves be biologically active orinactive.

Protected compounds may also exhibit altered, and in some cases,optimized properties in vitro and in vivo, such as passage throughcellular membranes and resistance to enzymatic degradation orsequestration. In this role, protected compounds with intendedtherapeutic effects may be referred to as prodrugs. Another function ofa protecting group is to convert the parental drug into a prodrug,whereby the parental drug is released upon conversion of the prodrug invivo. Because active prodrugs may be absorbed more effectively than theparental drug, prodrugs may possess greater potency in vivo than theparental drug. Protecting groups are removed either in vitro, in theinstance of chemical intermediates, or in vivo, in the case of prodrugs.With chemical intermediates, it is not particularly important that theresulting products after deprotection, e.g., alcohols, bephysiologically acceptable, although in general it is more desirable ifthe products are pharmacologically innocuous.

“Prodrug moiety” means a labile functional group which separates fromthe active inhibitory compound during metabolism, systemically, inside acell, by hydrolysis, enzymatic cleavage, or by some other process(Bundgaard, Hans, “Design and Application of Prodrugs” in (1991), P.Krogsgaard-Larsen and H. Bundgaard, Eds. Harwood Academic PublishersTextbook of Drug Design and Development, pp. 113-191). Enzymes which arecapable of an enzymatic activation mechanism with the phosphonateprodrug compounds of the invention include, but are not limited to,amidases, esterases, microbial enzymes, phospholipases, cholinesterases,and phosphases. Prodrug moieties can serve to enhance solubility,absorption and lipophilicity to optimize drug delivery, bioavailabilityand efficacy.

A prodrug moiety may include an active metabolite or drug itself.

Exemplary prodrug moieties include the hydrolytically sensitive orlabile acyloxymethyl esters —CH₂OC(═O)R³⁰ and acyloxymethyl carbonates—CH₂C(═O)OR³⁰ where R³⁰ is C₁-C₆ alkyl, C₁-C₆ substituted alkyl, C₆-C₂₀aryl or C₆-C₂₀ substituted aryl. The acyloxyalkyl ester was used as aprodrug strategy for carboxylic acids and then applied to phosphates andphosphonates by Farquhar et al. (1983) J. Pharm. Sci. 72: 324; also U.S.Pat. Nos. 4,816,570, 4,968,788, 5,663,159 and 5792756. In certaincompounds of the invention, a prodrug moiety is part of a phosphategroup. The acyloxyalkyl ester may be used to deliver phosphoric acidsacross cell membranes and to enhance oral bioavailability. A closevariant of the acyloxyalkyl ester, the alkoxycarbonyloxyalkyl ester(carbonate), may also enhance oral bioavailability as a prodrug moietyin the compounds of the combinations of the invention. An exemplaryacyloxymethyl ester is pivaloyloxymethoxy, (POM) —CH₂C(═O)C(CH₃)₃. Anexemplary acyloxymethyl carbonate prodrug moiety ispivaloyloxymethylcarbonate (POC) —CH₂C(═O)OC(CH₃)₃.

The phosphate group may be a phosphate prodrug moiety. The prodrugmoiety may be sensitive to hydrolysis, such as, but not limited to thosecomprising a pivaloyloxymethyl carbonate (POC) or POM group.Alternatively, the prodrug moiety may be sensitive to enzymaticpotentiated cleavage, such as a lactate ester or a phosphonamidate-estergroup.

Aryl esters of phosphorus groups, especially phenyl esters, are reportedto enhance oral bioavailability (DeLambert et al. (1994) J. Med. Chem.37: 498). Phenyl esters containing a carboxylic ester ortho to thephosphate have also been described (Khamnei and Torrence, (1996) J. Med.Chem. 39:4109-4115). Benzyl esters are reported to generate the parentphosphonic acid. In some cases, substituents at the ortho-orpara-position may accelerate the hydrolysis. Benzyl analogs with anacylated phenol or an alkylated phenol may generate the phenoliccompound through the action of enzymes, e.g., esterases, oxidases, etc.,which in turn undergoes cleavage at the benzylic C—O bond to generatethe phosphoric acid and the quinone methide intermediate. Examples ofthis class of prodrugs are described by Mitchell et al. (1992) J. Chem.Soc. Perkin Trans. I 2345; Brook et al. WO 91/19721. Still otherbenzylic prodrugs have been described containing a carboxylicester-containing group attached to the benzylic methylene (Glazier etal. WO 91/19721). Thio-containing prodrugs are reported to be useful forthe intracellular delivery of phosphonate drugs. These proesters containan ethylthio group in which the thiol group is either esterified with anacyl group or combined with another thiol group to form a disulfide.Deesterification or reduction of the disulfide generates the free thiointermediate which subsequently breaks down to the phosphoric acid andepisulfide (Puech et al. (1993) Antiviral Res., 22: 155-174; Benzaria etal. (1996) J. Med. Chem. 39: 4958). Cyclic phosphonate esters have alsobeen described as prodrugs of phosphorus-containing compounds (Erion etal., U.S. Pat. No. 6,312,662).

It is to be noted that all enantiomers, diastereomers, and racemicmixtures, tautomers, polymorphs, pseudopolymorphs of compounds withinthe scope of Formula I-V and pharmaceutically acceptable salts thereofare embraced by the present invention. All mixtures of such enantiomersand diastereomers are within the scope of the present invention.

A compound of Formula I-V and its pharmaceutically acceptable salts mayexist as different polymorphs or pseudopolymorphs. As used herein,crystalline polymorphism means the ability of a crystalline compound toexist in different crystal structures. The crystalline polymorphism mayresult from differences in crystal packing (packing polymorphism) ordifferences in packing between different conformers of the same molecule(conformational polymorphism). As used herein, crystallinepseudopolymorphism means the ability of a hydrate or solvate of acompound to exist in different crystal structures. The pseudopolymorphsof the instant invention may exist due to differences in crystal packing(packing pseudopolymorphism) or due to differences in packing betweendifferent conformers of the same molecule (conformationalpseudopolymorphism). The instant invention comprises all polymorphs andpseudopolymorphs of the compounds of Formula I-V and theirpharmaceutically acceptable salts.

A compound of Formula I-V and its pharmaceutically acceptable salts mayalso exist as an amorphous solid. As used herein, an amorphous solid isa solid in which there is no long-range order of the positions of theatoms in the solid. This definition applies as well when the crystalsize is two nanometers or less. Additives, including solvents, may beused to create the amorphous forms of the instant invention. The instantinvention comprises all amorphous forms of the compounds of Formula I-Vand their pharmaceutically acceptable salts.

Selected substituents comprising the compounds of Formula I-V arepresent to a recursive degree. In this context, “recursive substituent”means that a substituent may recite another instance of itself. Becauseof the recursive nature of such substituents, theoretically, a largenumber of compounds may be present in any given embodiment. For example,R^(x) comprises a R^(y) substituent. R^(y) can be R. R can be W³. W³ canbe W⁴ and W⁴ can be R or comprise substituents comprising R. One ofordinary skill in the art of medicinal chemistry understands that thetotal number of such substituents is reasonably limited by the desiredproperties of the compound intended. Such properties include, by way ofexample and not limitation, physical properties such as molecularweight, solubility or log P, application properties such as activityagainst the intended target, and practical properties such as ease ofsynthesis.

By way of example and not limitation, W³ and R^(y) are recursivesubstituents in certain embodiments. Typically, each recursivesubstituent can independently occur 20, 19, 18, 17, 16, 15, 14, 13, 12,11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, or 0, times in a given embodiment.More typically, each recursive substituent can independently occur 12 orfewer times in a given embodiment. Even more typically, each recursivesubstituent can independently occur 3 or fewer times in a givenembodiment. For example, W³ will occur 0 to 8 times, R^(y) will occur 0to 6 times in a given embodiment. Even more typically, W³ will occur 0to 6 times and R^(y) will occur 0 to 4 times in a given embodiment.

Recursive substituents are an intended aspect of the invention. One ofordinary skill in the art of medicinal chemistry understands theversatility of such substituents. To the degree that recursivesubstituents are present in an embodiment of the invention, the totalnumber will be determined as set forth above.

The modifier “about” used in connection with a quantity is inclusive ofthe stated value and has the meaning dictated by the context (e.g.,includes the degree of error associated with measurement of theparticular quantity).

The compounds of the Formula I-V may comprise a phosphate group as R⁷,which may be a prodrug moiety

wherein each Y or Y¹ is, independently, O, S, NR, ⁺N(O)(R), N(OR),⁺N(O)(OR), or N—NR₂; W¹ and W², when taken together, are—Y³(C(R^(y))₂)₃Y³—; or one of W¹ or W² together with either R³ or R⁴ is—Y³— and the other of W¹ or W² is Formula Ib; or W¹ and W² are each,independently, a group of Formula Ib:

wherein:

each Y² is independently a bond, O, CR₂, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR),N—NR₂, S, S—S, S(O), or S(O)₂;

each Y³ is independently O, S, or NR;

M2 is 0, 1 or 2;

each R^(y) is independently H, F, Cl, Br, I, OH, R, —C(═Y¹)R, —C(═Y¹)OR,—C(═Y¹)N(R)₂, —N(R)₂, —⁺N(R)₃, —SR, —S(O)R, —S(O)₂R, —S(O)(OR),—S(O)₂(OR), —OC(═Y¹)R, —OC(═Y¹)OR, —OC(═Y¹)(N(R)₂), —SC(═Y¹)R,—SC(═Y¹)OR, —SC(═Y¹)(N(R)₂), —N(R)C(═Y¹)R, —N(R)C(═Y¹)OR, or—N(R)C(═Y¹)N(R)₂, —SO₂NR₂, —CN, —N₃, —NO₂, —OR, a protecting group orW³; or when taken together, two R^(y) on the same carbon atom form acarbocyclic ring of 3 to 7 carbon atoms;

each R⁸ is independently R^(y), a protecting group, or the formula:

wherein:

M1a, M1c, and M1d are independently 0 or 1;

M1b is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12;

each R is H, halogen, (C₁-C₈) alkyl, (C₁-C₈) substituted alkyl, (C₂-C₈)alkenyl, (C₂-C₈) substituted alkenyl, (C₂-C₈) alkynyl, (C₂-C₈)substituted alkynyl, C₆-C₂₀ aryl, C₆-C₂₀ substituted aryl, (C₂-C₂₀)heterocycle, (C₂-C₂₀) substituted heterocyclyl, arylalkyl, substitutedarylalkyl or a protecting group;

W³ is W⁴ or W⁵; W⁴ is R, —C(Y¹)R^(y), —C(Y¹)W⁵, —SO₂R^(y), or —SO₂W⁵;and W⁵ is a carbocycle or a heterocycle wherein W⁵ is independentlysubstituted with 0 to 3 R^(y) groups.

W⁵ carbocycles and W⁵ heterocycles may be independently substituted with0 to 3 R^(y) groups. W⁵ may be a saturated, unsaturated or aromatic ringcomprising a mono- or bicyclic carbocycle or heterocycle. W⁵ may have 3to 10 ring atoms, e.g., 3 to 7 ring atoms. The W⁵ rings are saturatedwhen containing 3 ring atoms, saturated or mono-unsaturated whencontaining 4 ring atoms, saturated, or mono- or di-unsaturated whencontaining 5 ring atoms, and saturated, mono- or di-unsaturated, oraromatic when containing 6 ring atoms.

A W⁵ heterocycle may be a monocycle having 3 to 7 ring members (2 to 6carbon atoms and 1 to 3 heteroatoms selected from N, O, P, and S) or abicycle having 7 to 10 ring members (4 to 9 carbon atoms and 1 to 3heteroatoms selected from N, O, P, and S). W⁵ heterocyclic monocyclesmay have 3 to 6 ring atoms (2 to 5 carbon atoms and 1 to 2 heteroatomsselected from N, O, and S); or 5 or 6 ring atoms (3 to 5 carbon atomsand 1 to 2 heteroatoms selected from N and S). W⁵ heterocyclic bicycleshave 7 to 10 ring atoms (6 to 9 carbon atoms and 1 to 2 heteroatomsselected from N, O, and S) arranged as a bicyclo [4,5], [5,5], [5,6], or[6,6] system; or 9 to 10 ring atoms (8 to 9 carbon atoms and 1 to 2hetero atoms selected from N and S) arranged as a bicyclo [5,6] or [6,6]system. The W⁵ heterocycle may be bonded to Y² through a carbon,nitrogen, sulfur or other atom by a stable covalent bond.

W⁵ heterocycles include for example, pyridyl, dihydropyridyl isomers,piperidine, pyridazinyl, pyrimidinyl, pyrazinyl, s-triazinyl, oxazolyl,imidazolyl, thiazolyl, isoxazolyl, pyrazolyl, isothiazolyl, furanyl,thiofuranyl, thienyl, and pyrrolyl. W⁵ also includes, but is not limitedto, examples such as:

W⁵ carbocycles and heterocycles may be independently substituted with 0to 3 R groups, as defined above. For example, substituted W⁵ carbocyclesinclude:

Examples of substituted phenyl carbocycles include:

Embodiments of

Formula I-V compounds include substructures such as:

wherein each Y^(2b) is, independently, O or N(R). In another aspect ofthis embodiment, each Y^(2b) is O and each R^(x) is independently:

wherein M1b is 1, 2 or 3 and each Y² is independently a bond, O, CR₂, orS. In another aspect of this embodiment, one Y^(2b)—R^(x) is NH(R) andthe other Y^(2b)—R^(x) is O—R^(x) wherein R^(x) is:

wherein M1b is 2. In another aspect of this embodiment, each Y^(2b) is Oand each R^(x) is independently:

wherein M1b is 2. In another aspect of this embodiment, each Y^(2b) is Oand each R^(x) is independently:

wherein M1b is 1 and Y² is a bond, O, or CR₂.

Other embodiments of

Formulas I-V compounds include substructures such as:

wherein each Y³ is, independently, O or N(R). In another aspect of thisembodiment, each Y³ is O. In another aspect of this embodiment, thesubstructure is:

wherein R^(y) is W⁵ as defined herein.

Another embodiment of

of Formula I-V includes the substructures:

wherein each Y^(2c) is, independently, O, N(R^(y)) or S.

Another embodiment of

of Formula I-V compounds includes the substructures wherein one of W¹ orW² together with either R³ or R⁴ is —Y³— and the other of W¹ or W² isFormula Ib. Such an embodiment is represented by a compound of FormulaIc selected from:

In another aspect of the embodiment of Formula Id, each Y and Y³ is O.In another aspect of the embodiment of Formula Id, W¹ or W² isY^(2b)—R^(x); each Y, Y³ and Y^(2b) is O and R^(x) is:

wherein M1b is 1, 2 or 3 and each Y² is independently a bond, O, CR₂, orS. In another aspect of the embodiment of Formula Id, W¹ or W² isY^(2b)—R^(x); each Y, Y³ and Y^(2b) is O and R^(x) is:

wherein M1 b is 2. In another aspect of the embodiment of Formula Id, W¹or W² is Y^(2b)—R^(x); each Y, Y³ and Y^(2b) is O and R^(x) is:

wherein M1b is 1 and Y² is a bond, O, or CR₂.

Another embodiment of

of Formula I-V compounds includes a substructure:

wherein W⁵ is a carbocycle such as phenyl or substituted phenyl. Inanother aspect of this embodiment, the substructure is:

wherein Y^(2b) is O or N(R) and the phenyl carbocycle is substitutedwith 0 to 3 R groups. In another aspect of this embodiment of thesubstructure, R^(x) is:

wherein M1b is 1, 2 or 3 and each Y² is independently a bond, O, CR₂, orS.

Another embodiment of

of Formula I-V includes substructures:

The chiral carbon of the amino acid and lactate moieties may be eitherthe R or S configuration or the racemic mixture.

Another embodiment of

of Formula I-V is substructure

wherein each Y² is, independently, —O— or —NH—. In another aspect ofthis embodiment, R^(y) is (C₁-C₈) alkyl, (C₁-C₈) substituted alkyl,(C₂-C₈) alkenyl, (C₂-C₈) substituted alkenyl, (C₂-C₈) alkynyl or (C₂-C₈)substituted alkynyl. In another aspect of this embodiment, R^(y) is(C₁-C₈) alkyl, (C₁-C₈) substituted alkyl, (C₂-C₈) alkenyl, (C₂-C₈)substituted alkenyl, (C₂-C₈) alkynyl or (C₂-C₈) substituted alkynyl; andR is CH₃. In another aspect of this embodiment, R^(y) is (C₁-C₈) alkyl,(C₁-C₈) substituted alkyl, (C₂-C₈) alkenyl, (C₂-C₈) substituted alkenyl,(C₂-C₈) alkynyl or (C₂-C₈) substituted alkynyl; R is CH₃; and each Y² is—NH—. In a aspect of this embodiment, W¹ and W² are, independently,nitrogen-linked, naturally occurring amino acids or naturally occurringamino acid esters. In another aspect of this embodiment, W¹ and W² are,independently, naturally-occurring 2-hydroxy carboxylic acids ornaturally-occurring 2-hydroxy carboxylic acid esters wherein the acid orester is linked to P through the 2-hydroxy group.

Another embodiment of

of Formula I to V is substructure:

In one aspect of this embodiment, each R^(x) is, independently, (C₁-C₈)alkyl. In another aspect of this embodiment, each R^(x) is,independently, C₆-C₂₀ aryl or C₆-C₂₀ substituted aryl.

In one embodiment,

is selected from

In some embodiments, the group —R⁷—O—C(R⁸)—C(R⁵)—C(R³)(R⁴)— is of thefollowing formula:

Another embodiment of

of Formulas I-V is substructure

wherein W¹ and W² are independently selected from one of the formulas inTables 1.1-1.37 and Table 2.1 below. The variables used in Tables1.1-1.37 (e.g., W²³, R²¹, etc.) pertain only to Tables 1.1-1.37, unlessotherwise indicated.

The variables used in Tables 1.1 to 1.37 have the following definitions:

each R²¹ is independently H or (C₁-C₈)alkyl;

each R²² is independently H, R²¹, R²³ or R²⁴ wherein each R²⁴ isindependently substituted with 0 to 3 R²³;

each R²³ is independently R^(23a), R^(23b), R^(23c) or R^(23d), providedthat when R²³ is bound to a heteroatom, then R²³ is R^(23c) or R^(23d);

each R^(23a) is independently F, Cl, Br, I, —CN, N₃ or —NO₂;

each R^(23b) is independently Y²¹;

each R^(23c) is independently —R^(2x), —N(R^(2x))(R^(2x)), —SR^(2x),—S(O)R^(2x), —S(O)₂R^(2x), —S(O)(OR^(2x)), —S(O)₂(OR^(2x)),—OC(═Y²¹)R^(2x), —OC(═Y²¹)OR^(2x), —OC(═Y²¹)(N(R^(2x))(R^(2x))),—SC(═Y²¹)R^(2x), —SC(═Y²¹)OR^(2x), —SC(═Y²¹)(N(R^(2x))(R^(2X))),N(R^(2x))C(═Y²¹)R^(2x), —N(R^(2x))C(═Y²¹)OR^(2x), or—N(R^(2x))C(═Y²¹)(N(R^(2x))(R^(2x)));

each R^(23d) is independently —C(═Y²¹)R^(2x), —C(═Y²¹)OR^(2x) or—C(═Y²¹)(N(R^(2x))(R^(2x)));

each R^(2x) is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, aryl, heteroaryl; or two R^(2x) taken together with anitrogen to which they are both attached form a 3-to 7-memberedheterocyclic ring wherein any one carbon atom of said heterocyclic ringcan optionally be replaced with —O—, —S— or —NR²¹—; and wherein one ormore of the non-terminal carbon atoms of each said (C₁-C₈)alkyl may beoptionally replaced with —O—, —S— or —NR²¹—;

each R²⁴ is independently (C₁-C₈)alkyl, (C₂-C₈)alkenyl, or(C₂-C₈)alkynyl;

each R²⁵ is independently R²⁴ wherein each R²⁴ is substituted with 0 to3 R²³ groups;

each R^(25a) is independently (C₁-C₈)alkylene, (C₂-C₈)alkenylene, or(C₂-C₈)alkynylene any one of which said (C₁-C₈)alkylene,(C₂-C₈)alkenylene, or (C₂-C₈)alkynylene is substituted with 0-3 R²³groups;

each W²³ is independently W²⁴ or W²⁵;

each W²⁴ is independently R²⁵, —C(═Y²¹)R²⁵, —C(═Y²¹)W²⁵, —SO₂R²⁵, or—SO₂W²⁵;

each W²⁵ is independently carbocycle or heterocyclyl wherein W²⁵ isindependently substituted with 0 to 3 R²² groups; and

each Y²¹ is independently O or S.

TABLE 1.1

1

2

3

4

5

6

7

8

TABLE 1.2

9

10

11

TABLE 1.3

12

13

14

15

16

17

18

19

TABLE 1.4

20

21

22

TABLE 1.5

23

24

25

26

27

28

29

30

TABLE 1.6

31

32

33

TABLE 1.7

34

35

36

37

38

39

40

41

TABLE 1.8

42

43

44

45

46

47

48

49

TABLE 1.9

50

51

52

53

54

55

56

57

TABLE 1.10

58

59

60

TABLE 1.11

61

62

63

64

65

66

67

68

TABLE 1.12

69

70

71

TABLE 1.13

72

73

74

75

76

77

78

79

TABLE 1.14

80

81

82

TABLE 1.15

83

84

85

86

87

88

89

90

TABLE 1.16

91

92

93

94

95

96

97

98

TABLE 1.17

99

100

101

102

103

104

105

106

TABLE 1.18

107

108

109

TABLE 1.19

110

111

112

113

114

115

116

117

TABLE 1.20

118

119

120

TABLE 1.21

121

122

123

124

125

126

127

128

TABLE 1.22

129

130

131

TABLE 1.23

132

133

134

135

136

137

138

139

TABLE 1.24

140

141

142

143

144

145

146

147

TABLE 1.25

148

149

150

151

152

153

154

155

156

157

158

159

TABLE 1.26

160

161

162

163

164

165

166

167

168

169

170

171

TABLE 1.27

172

173

174

175

176

177

178

179

TABLE 1.28

180

181

182

183

184

185

TABLE 1.29

186

187

188

189

190

191

192

193

TABLE 1.30

194

195

196

197

198

199

TABLE 1.31

200

201

202

203

204

205

206

207

TABLE 1.32

208

209

210

211

212

213

TABLE 1.33

214

215

216

217

218

219

220

221

TABLE 1.34

222

223

224

225

226

227

TABLE 1.35

228

229

230

231

232

233

234

235

TABLE 1.36

236

237

238

239

240

241

242

243

TABLE 1.37

244

245

246

247

TABLE 2.1

67

68

69

70

71

258

248

249

250

251

252

253

254

255

256

257

Embodiments of R^(x) include esters, carbamates, carbonates, thioesters,amides, thioamides, and urea groups:

Any reference to the compounds of the invention described herein alsoincludes a reference to a physiologically acceptable salt thereof.Examples of physiologically acceptable salts of the compounds of theinvention include salts derived from an appropriate base, such as analkali metal or an alkaline earth (for example, Na⁺, Li⁺, K⁺, Ca⁺² andMg⁺²), ammonium and NR₄ ⁺ (wherein R is defined herein). Physiologicallyacceptable salts of a nitrogen atom or an amino group include (a) acidaddition salts formed with inorganic acids, for example, hydrochloricacid, hydrobromic acid, sulfuric acid, sulfamic acids, phosphoric acid,nitric acid and the like; (b) salts formed with organic acids such as,for example, acetic acid, oxalic acid, tartaric acid, succinic acid,maleic acid, fumaric acid, gluconic acid, citric acid, malic acid,ascorbic acid, benzoic acid, isethionic acid, lactobionic acid, tannicacid, palmitic acid, alginic acid, polyglutamic acid,naphthalenesulfonic acid, methanesulfonic acid, p-toluenesulfonic acid,benzenesulfonic acid, naphthalenedisulfonic acid, polygalacturonic acid,malonic acid, sulfosalicylic acid, glycolic acid,2-hydroxy-3-naphthoate, pamoate, salicylic acid, stearic acid, phthalicacid, mandelic acid, lactic acid, ethanesulfonic acid, lysine, arginine,glutamic acid, glycine, serine, threonine, alanine, isoleucine, leucineand the like; and (c) salts formed from elemental anions for example,chlorine, bromine, and iodine. Physiologically acceptable salts of acompound of a hydroxy group include the anion of said compound incombination with a suitable cation such as Na⁺ and NR₄ ⁺.

For therapeutic use, salts of active ingredients of the compounds of theinvention will be physiologically acceptable, i.e., they will be saltsderived from a physiologically acceptable acid or base. However, saltsof acids or bases which are not physiologically acceptable may also finduse, for example, in the preparation or purification of aphysiologically acceptable compound. All salts, whether or not derivedfrom a physiologically acceptable acid or base, are within the scope ofthe present invention.

Finally, it is to be understood that the compositions herein comprisecompounds of the invention in their un-ionized, as well as zwitterionicform, and combinations with stoichiometric amounts of water as inhydrates.

The compounds of the invention, exemplified by Formula I-V may havechiral centers, e.g., chiral carbon or phosphorus atoms. The compoundsof the invention thus include racemic mixtures of all stereoisomers,including enantiomers, diastereomers, and atropisomers. In addition, thecompounds of the invention include enriched or resolved optical isomersat any or all asymmetric, chiral atoms. In other words, the chiralcenters apparent from the depictions are provided as the chiral isomersor racemic mixtures. Both racemic and diastereomeric mixtures, as wellas the individual optical isomers isolated or synthesized, substantiallyfree of their enantiomeric or diastereomeric partners, are all withinthe scope of the invention. The racemic mixtures are separated intotheir individual, substantially optically pure isomers throughwell-known techniques such as, for example, the separation ofdiastereomeric salts formed with optically active adjuncts, e.g., acidsor bases followed by conversion back to the optically active substances.In most instances, the desired optical isomer is synthesized by means ofstereospecific reactions, beginning with the appropriate stereoisomer ofthe desired starting material.

The term “chiral” refers to molecules which have the property ofnon-superimposability of the mirror image partner, while the term“achiral” refers to molecules which are superimposable on their mirrorimage partner.

The term “stereoisomers” refers to compounds which have identicalchemical constitution, but differ with regard to the arrangement of theatoms or groups in space.

“Diastereomer” refers to a stereoisomer with two or more centers ofchirality and whose molecules are not mirror images of one another.Diastereomers have different physical properties, e.g., melting points,boiling points, spectral properties, and reactivities. Mixtures ofdiastereomers may separate under high resolution analytical proceduressuch as electrophoresis and chromatography.

“Enantiomers” refer to two stereoisomers of a compound which arenon-superimposable mirror images of one another.

Stereochemical definitions and conventions used herein generally followS. P. Parker, Ed., McGraw-Hill Dictionary of Chemical Terms (1984)McGraw-Mill Book Company, New York; and Eliel, E. and Wilen, S.,Stereochemistry of Organic Compounds (1994) John Wiley & Sons, Inc., NewYork. Many organic compounds exist in optically active forms, i.e., theyhave the ability to rotate the plane of plane-polarized light. Indescribing an optically active compound, the prefixes D and L or R and Sare used to denote the absolute configuration of the molecule about itschiral center(s). The prefixes d and I, D and L, or (+) and (−) areemployed to designate the sign of rotation of plane-polarized light bythe compound, with S, (−), or 1 meaning that the compound islevorotatory while a compound prefixed with R, (+), or d isdextrorotatory. For a given chemical structure, these stereoisomers areidentical except that they are mirror images of one another. A specificstereoisomer may also be referred to as an enantiomer, and a mixture ofsuch isomers is often called an enantiomeric mixture. A 50:50 mixture ofenantiomers is referred to as a racemic mixture or a racemate, which mayoccur where there has been no stereoselection or stereospecificity in achemical reaction or process. The terms “racemic mixture” and “racemate”refer to an equimolar mixture of two enantiomeric species, devoid ofoptical activity.

Whenever a compound described herein is substituted with more than oneof the same designated group, e.g., “R” or “R¹”, then it will beunderstood that the groups may be the same or different, i.e., eachgroup is independently selected. Wavy lines,

, indicate the site of covalent bond attachments to the adjoiningsubstructures, groups, moieties, or atoms.

The compounds of the invention can also exist as tautomeric isomers incertain cases. Although only one delocalized resonance structure may bedepicted, all such forms are contemplated within the scope of theinvention. For example, ene-amine tautomers can exist for purine,pyrimidine, imidazole, guanidine, amidine, and tetrazole systems and alltheir possible tautomeric forms are within the scope of the invention.

Methods of Inhibition of HCV Polymerase

Another aspect of the invention relates to methods of inhibiting theactivity of HCV polymerase comprising the step of treating a samplesuspected of containing HCV with a composition of the invention.

Compositions of the invention may act as inhibitors of HCV polymerase,as intermediates for such inhibitors or have other utilities asdescribed below. The inhibitors will bind to locations on the surface orin a cavity of HCV polymerase having a geometry unique to HCVpolymerase. Compositions binding HCV polymerase may bind with varyingdegrees of reversibility. Those compounds binding substantiallyirreversibly are ideal candidates for use in this method of theinvention. Once labeled, the substantially irreversibly bindingcompositions are useful as probes for the detection of HCV polymerase.Accordingly, the invention relates to methods of detecting HCVpolymerase in a sample suspected of containing HCV polymerase comprisingthe steps of: treating a sample suspected of containing HCV polymerasewith a composition comprising a compound of the invention bound to alabel; and observing the effect of the sample on the activity of thelabel. Suitable labels are well known in the diagnostics field andinclude stable free radicals, fluorophores, radioisotopes, enzymes,chemiluminescent groups and chromogens. The compounds herein are labeledin conventional fashion using functional groups such as hydroxyl,carboxyl, sulfhydryl or amino.

Within the context of the invention, samples suspected of containing HCVpolymerase include natural or man-made materials such as livingorganisms; tissue or cell cultures; biological samples such asbiological material samples (blood, serum, urine, cerebrospinal fluid,tears, sputum, saliva, tissue samples, and the like); laboratorysamples; food, water, or air samples; bioproduct samples such asextracts of cells, particularly recombinant cells synthesizing a desiredglycoprotein; and the like. Typically the sample will be suspected ofcontaining an organism which produces HCV polymerase, frequently apathogenic organism such as HCV. Samples can be contained in any mediumincluding water and organic solvent\water mixtures. Samples includeliving organisms such as humans, and man made materials such as cellcultures.

The treating step of the invention comprises adding the composition ofthe invention to the sample or it comprises adding a precursor of thecomposition to the sample. The addition step comprises any method ofadministration as described above.

If desired, the activity of HCV polymerase after application of thecomposition can be observed by any method including direct and indirectmethods of detecting HCV polymerase activity. Quantitative, qualitative,and semiquantitative methods of determining HCV polymerase activity areall contemplated. Typically one of the screening methods described aboveare applied, however, any other method such as observation of thephysiological properties of a living organism are also applicable.

Organisms that contain HCV polymerase include the HCV virus. Thecompounds of this invention are useful in the treatment or prophylaxisof HCV infections in animals or in man.

However, in screening compounds capable of inhibiting humanimmunodeficiency viruses, it should be kept in mind that the results ofenzyme assays may not correlate with cell culture assays. Thus, a cellbased assay should be the primary screening tool.

Screens for HCV Polymerase Inhibitors

Compositions of the invention are screened for inhibitory activityagainst HCV polymerase by any of the conventional techniques forevaluating enzyme activity. Within the context of the invention,typically compositions are first screened for inhibition of HCVpolymerase in vitro and compositions showing inhibitory activity arethen screened for activity in vivo. Compositions having in vitro Ki(inhibitory constants) of less then about 5×10⁻⁶ M and preferably lessthan about 1×10⁻⁷ M are preferred for in vivo use.

Useful in vitro screens have been described in detail and will not beelaborated here. However, the examples describe suitable in vitroassays.

Pharmaceutical Formulations

The compounds of this invention are formulated with conventionalcarriers and excipients, which will be selected in accord with ordinarypractice. Tablets will contain excipients, glidants, fillers, bindersand the like. Aqueous formulations are prepared in sterile form, andwhen intended for delivery by other than oral administration generallywill be isotonic. All formulations will optionally contain excipientssuch as those set forth in the “Handbook of Pharmaceutical Excipients”(1986). Excipients include ascorbic acid and other antioxidants,chelating agents such as EDTA, carbohydrates such as dextran,hydroxyalkylcellulose, hydroxyalkylmethylcellulose, stearic acid and thelike. The pH of the formulations ranges from about 3 to about 11, but isordinarily about 7 to 10.

While it is possible for the active ingredients to be administeredalone, it may be preferable to present them as pharmaceuticalformulations. The formulations, both for veterinary and for human use,of the invention comprise at least one active ingredient, as abovedefined, together with one or more acceptable carriers and optionallyother therapeutic ingredients. The carrier(s) must be “acceptable” inthe sense of being compatible with the other ingredients of theformulation and physiologically innocuous to the recipient thereof.

The formulations include those suitable for the foregoing administrationroutes. The formulations may conveniently be presented in unit dosageform and may be prepared by any of the methods well known in the art ofpharmacy. Techniques and formulations generally are found in Remington'sPharmaceutical Sciences (Mack Publishing Co., Easton, Pa.). Such methodsinclude the step of bringing into association the active ingredient withthe carrier which constitutes one or more accessory ingredients. Ingeneral the formulations are prepared by uniformly and intimatelybringing into association the active ingredient with liquid carriers orfinely divided solid carriers or both, and then, if necessary, shapingthe product.

Formulations of the present invention suitable for oral administrationmay be presented as discrete units such as capsules, cachets or tabletseach containing a predetermined amount of the active ingredient; as apowder or granules; as a solution or a suspension in an aqueous ornon-aqueous liquid; or as an oil-in-water liquid emulsion or awater-in-oil liquid emulsion. The active ingredient may also beadministered as a bolus, electuary or paste.

A tablet is made by compression or molding, optionally with one or moreaccessory ingredients. Compressed tablets may be prepared by compressingin a suitable machine the active ingredient in a free-flowing form suchas a powder or granules, optionally mixed with a binder, lubricant,inert diluent, preservative, surface active or dispersing agent. Moldedtablets may be made by molding in a suitable machine a mixture of thepowdered active ingredient moistened with an inert liquid diluent. Thetablets may optionally be coated or scored and optionally are formulatedso as to provide slow or controlled release of the active ingredienttherefrom.

For infections of the eye or other external tissues e.g., mouth andskin, the formulations are preferably applied as a topical ointment orcream containing the active ingredient(s) in an amount of, for example,0.075 to 20% w/w (including active ingredient(s) in a range between 0.1%and 20% in increments of 0.1% w/w such as 0.6% w/w, 0.7% w/w, etc.),preferably 0.2 to 15% w/w and most preferably 0.5 to 10% w/w. Whenformulated in an ointment, the active ingredients may be employed witheither a paraffinic or a water-miscible ointment base. Alternatively,the active ingredients may be formulated in a cream with an oil-in-watercream base.

If desired, the aqueous phase of the cream base may include, forexample, at least 30% w/w of a polyhydric alcohol, i.e., an alcoholhaving two or more hydroxyl groups such as propylene glycol, butane1,3-diol, mannitol, sorbitol, glycerol and polyethylene glycol(including PEG 400) and mixtures thereof. The topical formulations maydesirably include a compound which enhances absorption or penetration ofthe active ingredient through the skin or other affected areas. Examplesof such dermal penetration enhancers include dimethyl sulphoxide andrelated analogs.

The oily phase of the emulsions of this invention may be constitutedfrom known ingredients in a known manner. While the phase may comprisemerely an emulsifier (otherwise known as an emulgent), it desirablycomprises a mixture of at least one emulsifier with a fat or an oil orwith both a fat and an oil. Preferably, a hydrophilic emulsifier isincluded together with a lipophilic emulsifier which acts as astabilizer. It is also preferred to include both an oil and a fat.Together, the emulsifier(s) with or without stabilizer(s) make up theso-called emulsifying wax, and the wax together with the oil and fatmake up the so-called emulsifying ointment base which forms the oilydispersed phase of the cream formulations.

Emulgents and emulsion stabilizers suitable for use in the formulationof the invention include Tween® 60, Span® 80, cetostearyl alcohol,benzyl alcohol, myristyl alcohol, glyceryl mono-stearate and sodiumlauryl sulfate.

The choice of suitable oils or fats for the formulation is based onachieving the desired cosmetic properties. The cream should preferablybe a non-greasy, non-staining and washable product with suitableconsistency to avoid leakage from tubes or other containers. Straight orbranched chain, mono- or dibasic alkyl esters such as di-isoadipate,isocetyl stearate, propylene glycol diester of coconut fatty acids,isopropyl myristate, decyl oleate, isopropyl palmitate, butyl stearate,2-ethylhexyl palmitate or a blend of branched chain esters known asCrodamol CAP may be used, the last three being preferred esters. Thesemay be used alone or in combination depending on the propertiesrequired. Alternatively, high melting point lipids such as white softparaffin and/or liquid paraffin or other mineral oils are used.

Pharmaceutical formulations according to the present invention comprisea combination according to the invention together with one or morepharmaceutically acceptable carriers or excipients and optionally othertherapeutic agents. Pharmaceutical formulations containing the activeingredient may be in any form suitable for the intended method ofadministration. When used for oral use, for example, tablets, troches,lozenges, aqueous or oil suspensions, dispersible powders or granules,emulsions, hard or soft capsules, syrups or elixirs may be prepared.Compositions intended for oral use may be prepared according to anymethod known to the art for the manufacture of pharmaceuticalcompositions and such compositions may contain one or more agentsincluding sweetening agents, flavoring agents, coloring agents andpreserving agents, in order to provide a palatable preparation. Tabletscontaining the active ingredient in admixture with non-toxicpharmaceutically acceptable excipient which are suitable for manufactureof tablets are acceptable. These excipients may be, for example, inertdiluents, such as calcium or sodium carbonate, lactose, calcium orsodium phosphate; granulating and disintegrating agents, such as maizestarch, or alginic acid; binding agents, such as starch, gelatin oracacia; and lubricating agents, such as magnesium stearate, stearic acidor talc. Tablets may be uncoated or may be coated by known techniquesincluding microencapsulation to delay disintegration and adsorption inthe gastrointestinal tract and thereby provide a sustained action over alonger period. For example, a time delay material such as glycerylmonostearate or glyceryl distearate alone or with a wax may be employed.

Formulations for oral use may be also presented as hard gelatin capsuleswhere the active ingredient is mixed with an inert solid diluent, forexample, calcium phosphate or kaolin, or as soft gelatin capsuleswherein the active ingredient is mixed with water or an oil medium, suchas peanut oil, liquid paraffin or olive oil.

Aqueous suspensions of the invention contain the active materials inadmixture with excipients suitable for the manufacture of aqueoussuspensions. Such excipients include a suspending agent, such as sodiumcarboxymethylcellulose, methylcellulose, hydroxypropyl methylcelluose,sodium alginate, polyvinylpyrrolidone, gum tragacanth and gum acacia,and dispersing or wetting agents such as a naturally-occurringphosphatide (e.g., lecithin), a condensation product of an alkyleneoxide with a fatty acid (e.g., polyoxyethylene stearate), a condensationproduct of ethylene oxide with a long chain aliphatic alcohol (e.g.,heptadecaethyleneoxycetanol), a condensation product of ethylene oxidewith a partial ester derived from a fatty acid and a hexitol anhydride(e.g., polyoxyethylene sorbitan monooleate). The aqueous suspension mayalso contain one or more preservatives such as ethyl or n-propylp-hydroxy-benzoate, one or more coloring agents, one or more flavoringagents and one or more sweetening agents, such as sucrose or saccharin.

Oil suspensions may be formulated by suspending the active ingredient ina vegetable oil, such as arachis oil, olive oil, sesame oil or coconutoil, or in a mineral oil such as liquid paraffin. The oral suspensionsmay contain a thickening agent, such as beeswax, hard paraffin or cetylalcohol. Sweetening agents, such as those set forth above, and flavoringagents may be added to provide a palatable oral preparation. Thesecompositions may be preserved by the addition of an antioxidant such asascorbic acid.

Dispersible powders and granules of the invention suitable forpreparation of an aqueous suspension by the addition of water providethe active ingredient in admixture with a dispersing or wetting agent, asuspending agent, and one or more preservatives. Suitable dispersing orwetting agents and suspending agents are exemplified by those disclosedabove. Additional excipients, for example, sweetening, flavoring andcoloring agents, may also be present.

The pharmaceutical compositions of the invention may also be in the formof oil-in-water emulsions. The oily phase may be a vegetable oil, suchas olive oil or arachis oil, a mineral oil, such as liquid paraffin, ora mixture of these. Suitable emulsifying agents includenaturally-occurring gums, such as gum acacia and gum tragacanth,naturally-occurring phosphatides, such as soybean lecithin, esters orpartial esters derived from fatty acids and hexitol anhydrides, such assorbitan monooleate, and condensation products of these partial esterswith ethylene oxide, such as polyoxyethylene sorbitan monooleate. Theemulsion may also contain sweetening and flavoring agents. Syrups andelixirs may be formulated with sweetening agents, such as glycerol,sorbitol or sucrose. Such formulations may also contain a demulcent, apreservative, a flavoring or a coloring agent.

The pharmaceutical compositions of the invention may be in the form of asterile injectable preparation, such as a sterile injectable aqueous oroleaginous suspension. This suspension may be formulated according tothe known art using those suitable dispersing or wetting agents andsuspending agents which have been mentioned above.

The sterile injectable preparation may also be a sterile injectablesolution or suspension in a non-toxic parenterally acceptable diluent orsolvent, such as a solution in 1,3-butane-diol or prepared as alyophilized powder. Among the acceptable vehicles and solvents that maybe employed are water, Ringer's solution and isotonic sodium chloridesolution. In addition, sterile fixed oils may conventionally be employedas a solvent or suspending medium. For this purpose, any bland fixed oilmay be employed including synthetic mono- or diglycerides. In addition,fatty acids such as oleic acid may likewise be used in the preparationof injectables.

The amount of active ingredient that may be combined with the carriermaterial to produce a single dosage form will vary depending upon thehost treated and the particular mode of administration. For example, atime-release formulation intended for oral administration to humans maycontain approximately 1 to 1000 mg of active material compounded with anappropriate and convenient amount of carrier material which may varyfrom about 5 to about 95% of the total compositions (weight:weight). Thepharmaceutical composition can be prepared to provide easily measurableamounts for administration. For example, an aqueous solution intendedfor intravenous infusion may contain from about 3 to 500 mg of theactive ingredient per milliliter of solution in order that infusion of asuitable volume at a rate of about 30 mL/hr can occur.

Formulations suitable for topical administration to the eye also includeeye drops wherein the active ingredient is dissolved or suspended in asuitable carrier, especially an aqueous solvent for the activeingredient. The active ingredient is preferably present in suchformulations in a concentration of 0.5 to 20%, advantageously 0.5 to10%, and particularly about 1.5% w/w.

Formulations suitable for topical administration in the mouth includelozenges comprising the active ingredient in a flavored basis, usuallysucrose and acacia or tragacanth; pastilles comprising the activeingredient in an inert basis such as gelatin and glycerin, or sucroseand acacia; and mouthwashes comprising the active ingredient in asuitable liquid carrier.

Formulations for rectal administration may be presented as a suppositorywith a suitable base comprising for example, cocoa butter or asalicylate.

Formulations suitable for intrapulmonary or nasal administration have aparticle size, for example, in the range of 0.1 to 500 microns, such as0.5, 1, 30, 35 etc., which is administered by rapid inhalation throughthe nasal passage or by inhalation through the mouth so as to reach thealveolar sacs. Suitable formulations include aqueous or oily solutionsof the active ingredient. Formulations suitable for aerosol or drypowder administration may be prepared according to conventional methodsand may be delivered with other therapeutic agents such as compoundsheretofore used in the treatment or prophylaxis of HCV infections asdescribed below.

Formulations suitable for vaginal administration may be presented aspessaries, tampons, creams, gels, pastes, foams or spray formulationscontaining in addition to the active ingredient such carriers as areknown in the art to be appropriate.

Formulations suitable for parenteral administration include aqueous andnon-aqueous sterile injection solutions which may contain anti-oxidants,buffers, bacteriostats and solutes which render the formulation isotonicwith the blood of the intended recipient; and aqueous and non-aqueoussterile suspensions which may include suspending agents and thickeningagents.

The formulations are presented in unit-dose or multi-dose containers,for example, sealed ampoules and vials, and may be stored in afreeze-dried (lyophilized) condition requiring only the addition of thesterile liquid carrier, for example, water for injection, immediatelyprior to use. Extemporaneous injection solutions and suspensions areprepared from sterile powders, granules and tablets of the kindpreviously described. Preferred unit dosage formulations are thosecontaining a daily dose or unit daily sub-dose, as herein above recited,or an appropriate fraction thereof, of the active ingredient.

It should be understood that in addition to the ingredients particularlymentioned above the formulations of this invention may include otheragents conventional in the art having regard to the type of formulationin question, for example, those suitable for oral administration mayinclude flavoring agents.

The invention further provides veterinary compositions comprising atleast one active ingredient as above defined together with a veterinarycarrier therefore.

Veterinary carriers are materials useful for the purpose ofadministering the composition and may be solid, liquid or gaseousmaterials which are otherwise inert or acceptable in the veterinary artand are compatible with the active ingredient. These veterinarycompositions may be administered orally, parenterally or by any otherdesired route.

Compounds of the invention are used to provide controlled releasepharmaceutical formulations containing as active ingredient one or morecompounds of the invention (“controlled release formulations”) in whichthe release of the active ingredient are controlled and regulated toallow less frequency dosing or to improve the pharmacokinetic ortoxicity profile of a given active ingredient.

Effective dose of active ingredient depends at least on the nature ofthe condition being treated, toxicity, whether the compound is beingused prophylactically (lower doses) or against an active viralinfection, the method of delivery, and the pharmaceutical formulation,and will be determined by the clinician using conventional doseescalation studies. It can be expected to be from about 0.0001 to about100 mg/kg body weight per day; typically, from about 0.01 to about 10mg/kg body weight per day; more typically, from about 0.01 to about 5mg/kg body weight per day; most typically, from about 0.05 to about 0.5mg/kg body weight per day. For example, the daily candidate dose for anadult human of approximately 70 kg body weight will range from 1 mg to1000 mg, preferably between 5 mg and 500 mg, and may take the form ofsingle or multiple doses.

Routes of Administration

One or more compounds of the invention (herein referred to as the activeingredients) are administered by any route appropriate to the conditionto be treated.

Suitable routes include oral, rectal, nasal, topical (including buccaland sublingual), vaginal and parenteral (including subcutaneous,intramuscular, intravenous, intradermal, intrathecal and epidural), andthe like. It will be appreciated that the preferred route may vary with,for example, the condition of the recipient. An advantage of thecompounds of this invention is that they are orally bioavailable and canbe dosed orally.

Combination Therapy

Compositions of the invention are also used in combination with otheractive ingredients. For the treatment of HCV infections, preferably, theother active therapeutic ingredients or agents are interferons,ribavirin analogs, NS3 protease inhibitors, NS5a inhibitors, NS5bpolymerase inhibitors, alpha-glucosidase 1 inhibitors, cyclophilininhibitors, hepatoprotectants, other nucleoside inhibitors of HCV,non-nucleoside inhibitors of HCV, and other drugs for treating HCV.

Combinations of the compounds of Formula I-V are typically selectedbased on the condition to be treated, cross-reactivities of ingredientsand pharmaco-properties of the combination. For example, when treatingan infection (e.g., HCV), the compositions of the invention are combinedwith other active therapeutic agents (such as those described herein).

Suitable active therapeutic agents or ingredients which can be combinedwith the compounds of Formula I-V can include interferons, e.g.,pegylated rIFN-alpha 2b, pegylated rIFN-alpha 2a, rIFN-alpha 2b, IFNalpha-2b XL, rIFN-alpha 2a, consensus IFN alpha, infergen, rebif,locteron, AVI-005, PEG-infergen, pegylated IFN-beta, oral interferonalpha, feron, reaferon, intermax alpha, r-IFN-beta, infergen+actimmune,IFN-omega with DUROS, and albuferon; ribavirin analogs, e.g., rebetol,copegus, VX-497, and viramidine (taribavirin); NS5a inhibitors, e.g.,A-831, A-689 and BMS-790052; NS5b polymerase inhibitors, e.g., NM-283,valopicitabine, R1626, IDX184, PSI-7851, PSI-6130 (R1656), HCV-796, BILB1941, MK-0608, NM-107, R7128, VCH-759, PF-868554, GSK625433, andXTL-2125; NS3 protease inhibitors, e.g., SCH-503034 (SCH-7), VX-950(Telaprevir), ITMN-191, and BILN-2065; alpha-glucosidase 1 inhibitors,e.g., MX-3253 (celgosivir) and UT-231B; hepatoprotectants, e.g.,IDN-6556, ME 3738, MitoQ, and LB-84451; non-nucleoside inhibitors ofHCV, e.g., benzimidazole derivatives, benzo-1,2,4-thiadiazinederivatives, and phenylalanine derivatives; and other drugs for treatingHCV, e.g., zadaxin, nitazoxanide (alinea), BIVN-401 (virostat),DEBIO-025, VGX-410C, EMZ-702, AVI 4065, bavituximab, oglufanide, PYN-17,KPE02003002, actilon (CPG-10101), KRN-7000, civacir, GI-5005, ANA-975,XTL-6865, ANA 971, NOV-205, tarvacin, EHC-18, and NIM811.

In yet another embodiment, the present application disclosespharmaceutical compositions comprising a compound of the presentinvention, or a pharmaceutically acceptable salt, solvate, and/or esterthereof, in combination with at least one additional therapeutic agent,and a pharmaceutically acceptable carrier or excipient.

According to the present invention, the therapeutic agent used incombination with the compound of the present invention can be any agenthaving a therapeutic effect when used in combination with the compoundof the present invention. For example, the therapeutic agent used incombination with the compound of the present invention can beinterferons, ribavirin analogs, NS3 protease inhibitors, NS5ainhibitors, NS5b polymerase inhibitors alpha-glucosidase 1 inhibitors,cyclophilin inhibitors, hepatoprotectants, other nucleoside inhibitorsof HCV, non-nucleoside inhibitors of HCV, and other drugs for treatingHCV.

In another embodiment, the present application provides pharmaceuticalcompositions comprising a compound of the present invention, or apharmaceutically acceptable salt, solvate, and/or ester thereof, incombination with at least one additional therapeutic agent selected fromthe group consisting of pegylated rIFN-alpha 2b, pegylated rIFN-alpha2a, rIFN-alpha 2b, IFN alpha-2b XL, rIFN-alpha 2a, consensus IFN alpha,infergen, rebif, locteron, AVI-005, PEG-infergen, pegylated IFN-beta,oral interferon alpha, feron, reaferon, intermax alpha, r-IFN-beta,infergen+actimmune, IFN-omega with DUROS, albuferon, rebetol, copegus,VX-497, viramidine (taribavirin), A-831, A-689, NM-283, valopicitabine,R1626, PSI-6130 (R1656), IDX184, PSI-7851, HCV-796, BILB 1941, MK-0608,NM-107, R7128, VCH-759, PF-868554, GSK625433, XTL-2125, SCH-503034(SCH-7), VX-950 (Telaprevir), ITMN-191, and BILN-2065, MX-3253(celgosivir), UT-231B, IDN-6556, ME 3738, MitoQ, and LB-84451,benzimidazole derivatives, benzo-1,2,4-thiadiazine derivatives, andphenylalanine derivatives, zadaxin, nitazoxanide (alinea), BIVN-401(virostat), DEBIO-025, VGX-410C, EMZ-702, AVI 4065; bavituximab,oglufanide, PYN-17, KPE02003002, actilon (CPG-10101), KRN-7000, civacir,GI-5005, ANA-975, XTL-6865, ANA 971, NOV-205, tarvacin, EHC-18, andNIM811 and a pharmaceutically acceptable carrier or excipient.

In yet another embodiment, the present application provides acombination pharmaceutical agent comprising:

a) a first pharmaceutical composition comprising a compound of thepresent invention, or a pharmaceutically acceptable salt, solvate, orester thereof; and

b) a second pharmaceutical composition comprising at least oneadditional therapeutic agent selected from the group consisting of HIVprotease inhibiting compounds, HIV non-nucleoside inhibitors of reversetranscriptase, HIV nucleoside inhibitors of reverse transcriptase, HIVnucleotide inhibitors of reverse transcriptase, HIV integraseinhibitors, gp41 inhibitors, CXCR4 inhibitors, gp120 inhibitors, CCR5inhibitors, interferons, ribavirin analogs, NS3 protease inhibitors,NS5a inhibitors, alpha-glucosidase 1 inhibitors, cyclophilin inhibitors,hepatoprotectants, other nucleoside inhibitors of HCV, non-nucleosideinhibitors of HCV, and other drugs for treating HCV, and combinationsthereof.

Combinations of the compounds of Formula I-V and additional activetherapeutic agents may be selected to treat patients infected with HCVand other conditions such as HIV infections. Accordingly, the compoundsof Formula I-V may be combined with one or more compounds useful intreating HIV, for example, HIV protease inhibiting compounds, HIVnon-nucleoside inhibitors of reverse transcriptase, HIV nucleosideinhibitors of reverse transcriptase, HIV nucleotide inhibitors ofreverse transcriptase, HIV integrase inhibitors, gp41 inhibitors, CXCR4inhibitors, gp120 inhibitors, CCR5 inhibitors, interferons, ribavirinanalogs, NS3 protease inhibitors, NS5a inhibitors, alpha-glucosidase 1inhibitors, cyclophilin inhibitors, hepatoprotectants, other nucleosideinhibitors of HCV, non-nucleoside inhibitors of HCV, and other drugs fortreating HCV.

More specifically, one or more compounds of the present invention may becombined with one or more compounds selected from the group consistingof 1) HIV protease inhibitors, e.g., amprenavir, atazanavir,fosamprenavir, indinavir, lopinavir, ritonavir, lopinavir+ritonavir,nelfinavir, saquinavir, tipranavir, brecanavir, darunavir, TMC-126,TMC-114, mozenavir (DMP-450), JE-2147 (AG1776), AG1859, DG35, L-756423,R00334649, KNI-272, DPC-681, DPC-684, and GW640385X, DG17, PPL-100, 2) aHIV non-nucleoside inhibitor of reverse transcriptase, e.g.,capravirine, emivirine, delaviridine, efavirenz, nevirapine, (+)calanolide A, etravirine, GW5634, DPC-083, DPC-961, DPC-963, MIV-150,and TMC-120, TMC-278 (rilpivirine), efavirenz, BILR 355 BS, VRX 840773,UK-453,061, RDEA806, 3) a HIV nucleoside inhibitor of reversetranscriptase, e.g., zidovudine, emtricitabine, didanosine, stavudine,zalcitabine, lamivudine, abacavir, amdoxovir, elvucitabine, alovudine,MIV-210, racivir (±-FTC), D-d4FC, emtricitabine, phosphazide, fozivudinetidoxil, fosalvudine tidoxil, apricitibine (AVX754), amdoxovir, KP-1461,abacavir+lamivudine, abacavir+lamivudine+zidovudine,zidovudine+lamivudine, 4) a HIV nucleotide inhibitor of reversetranscriptase, e.g., tenofovir, tenofovir disoproxilfumarate+emtricitabine, tenofovir disoproxilfumarate+emtricitabine+efavirenz, and adefovir, 5) a HIV integraseinhibitor, e.g., curcumin, derivatives of curcumin, chicoric acid,derivatives of chicoric acid, 3,5-dicaffeoylquinic acid, derivatives of3,5-dicaffeoylquinic acid, aurintricarboxylic acid, derivatives ofaurintricarboxylic acid, caffeic acid phenethyl ester, derivatives ofcaffeic acid phenethyl ester, tyrphostin, derivatives of tyrphostin,quercetin, derivatives of quercetin, S-1360, zintevir (AR-177),L-870812, and L-870810, MK-0518 (raltegravir), BMS-707035, MK-2048,BA-011, BMS-538158, GSK364735C, 6) a gp41 inhibitor, e.g., enfuvirtide,sifuvirtide, FB006M, TRI-1144, SPC3, DES6, Locus gp41, CovX, and REP 9,7) a CXCR4 inhibitor, e.g., AMD-070, 8) an entry inhibitor, e.g., SP01A,TNX-355, 9) a gp120 inhibitor, e.g., BMS-488043 and BlockAide/CR, 10) aG6PD and NADH-oxidase inhibitor, e.g., immunitin, 10) a CCR5 inhibitor,e.g., aplaviroc, vicriviroc, INCB9471, PRO-140, INCB15050, PF-232798,CCR5 mAb004, and maraviroc, 11) an interferon, e.g., pegylatedrIFN-alpha 2b, pegylated rIFN-alpha 2a, rIFN-alpha 2b, IFN alpha-2b XL,rIFN-alpha 2a, consensus IFN alpha, infergen, rebif, locteron, AVI-005,PEG-infergen, pegylated IFN-beta, oral interferon alpha, feron,reaferon, intermax alpha, r-IFN-beta, infergen+actimmune, IFN-omega withDUROS, and albuferon, 12) ribavirin analogs, e.g., rebetol, copegus,VX-497, and viramidine (taribavirin) 13) NS5a inhibitors, e.g., A-831,A-689 and BMS-790052, 14) NS5b polymerase inhibitors, e.g., NM-283,valopicitabine, R1626, PSI-6130 (R1656), IDX184, PSI-7851, HCV-796, BILB1941, MK-0608, NM-107, R7128, VCH-759, PF-868554, GSK625433, andXTL-2125, 15) NS3 protease inhibitors, e.g., SCH-503034 (SCH-7), VX-950(Telaprevir), ITMN-191, and BILN-2065, 16) alpha-glucosidase 1inhibitors, e.g., MX-3253 (celgosivir) and UT-231B, 17)hepatoprotectants, e.g., IDN-6556, ME 3738, MitoQ, and LB-84451, 18)non-nucleoside inhibitors of HCV, e.g., benzimidazole derivatives,benzo-1,2,4-thiadiazine derivatives, and phenylalanine derivatives, 19)other drugs for treating HCV, e.g., zadaxin, nitazoxanide (alinea),BIVN-401 (virostat), DEBIO-025, VGX-410C, EMZ-702, AVI 4065,bavituximab, oglufanide, PYN-17, KPE02003002, actilon (CPG-10101),KRN-7000, civacir, GI-5005, ANA-975, XTL-6865, ANA 971, NOV-205,tarvacin, EHC-18, and NIM811, 19) pharmacokinetic enhancers, e.g.,BAS-100 and SPI452, 20)RNAse H inhibitors, e.g., ODN-93 and ODN-112, 21)other anti-HIV agents, e.g., VGV-1, PA-457 (bevirimat), ampligen,HRG214, cytolin, polymun, VGX-410, KD247, AMZ 0026, CYT 99007, A-221HIV, BAY 50-4798, MDX010 (iplimumab), PBS119, ALG889, and PA-1050040.

For the treatment of Paramyxoviridae virus infections, preferably, theother active therapeutic agent is active against Paramyxoviridae virusinfections, particularly respiratory syncytial virus infections and/orparainfluenza virus infections. Non-limiting examples of these otheractive therapeutic agents are ribavirin and/or palivizumab.

For the treatment of Orthomyxoviridae virus infections, preferably, theother active therapeutic agent is active against Orthomyxoviridae virusinfections, particularly Influenzavirus infections. Non-limitingexamples of these other active therapeutic agents are viral neuramidaseinhibitors and/or viral M2 channel inhibitors. Non-limiting examples ofneuramidase inhibitors include oseltamivir, zanamivir, laninamivir andperamivir. Non-limiting examples of viral M2 channel inhibitors includeamantadine and rimantadine.

For the treatment of Picornaviridae virus infections, preferably, theother active therapeutic agent is active against Picornaviridae virusinfections, particularly Enterovirus infections. Non-limiting examplesof these other active therapeutic agents are capsid binding inhibitorssuch as pleconaril, BTA-798 and other compounds disclosed by Wu, et al.(U.S. Pat. No. 7,078,403) and Watson (U.S. Pat. No. 7,166,604).

Many of the infections of the Paramyxoviridae, Orthomyxoviridae, andPicornaviridae viruses are respiratory infections. Therefore, additionalactive therapeutics used to treat respiratory symptoms and sequelae ofinfection may be used in combination with the compounds of Formula I-V.For example, other preferred additional therapeutic agents incombination with the compounds of Formula I-V for the treatment of viralrespiratory infections include, but are not limited to, bronchodilatorsand corticosteroids. Glucocorticoids, which were first introduced as anasthma therapy in 1950 (Carryer, Journal of Allergy, 21, 282-287, 1950),remain the most potent and consistently effective therapy for thisdisease, although their mechanism of action is not yet fully understood(Morris, J. Allergy Clin. Immunol., 75 (1 Pt) 1-13, 1985).Unfortunately, oral glucocorticoid therapies are associated withprofound undesirable side effects such as truncal obesity, hypertension,glaucoma, glucose intolerance, acceleration of cataract formation, bonemineral loss, and psychological effects, all of which limit their use aslong-term therapeutic agents (Goodman and Gilman, 10^(th) edition,2001). A solution to systemic side effects is to deliver steroid drugsdirectly to the site of inflammation. Inhaled corticosteroids (ICS) havebeen developed to mitigate the severe adverse effects of oral steroids.Non-limiting examples of corticosteroids that may be used incombinations with the compounds of Formula I-V are dexamethasone,dexamethasone sodium phosphate, fluorometholone, fluorometholoneacetate, loteprednol, loteprednol etabonate, hydrocortisone,prednisolone, fludrocortisones, triamcinolone, triamcinolone acetonide,betamethasone, beclomethasone diproprionate, methylprednisolone,fluocinolone, fluocinolone acetonide, flunisolide,fluocortin-21-butylate, flumethasone, flumetasone pivalate, budesonide,halobetasol propionate, mometasone furoate, fluticasone propionate,ciclesonide; or a pharmaceutically acceptable salts thereof.

Other anti-inflammatory agents working through anti-inflammatory cascademechanisms are also useful as additional therapeutic agents incombination with the compounds of Formula I-V for the treatment of viralrespiratory infections. Applying “anti-inflammatory signal transductionmodulators” (referred to in this text as AISTM), like phosphodiesteraseinhibitors (e.g., PDE-4, PDE-5, or PDE-7 specific), transcription factorinhibitors (e.g., blocking NFκB through IKK inhibition), or kinaseinhibitors (e.g., blocking P38 MAP, JNK, PI3K, EGFR or Syk) is a logicalapproach to switching off inflammation as these small molecules target alimited number of common intracellular pathways—those signaltransduction pathways that are critical points for the anti-inflammatorytherapeutic intervention (see review by P. J. Barnes, 2006). Thesenon-limiting additional therapeutic agents include:5-(2,4-Difluoro-phenoxy)-1-isobutyl-1H-indazole-6-carboxylic acid(2-dimethylamino-ethyl)-amide (P38 Map kinase inhibitor ARRY-797);3-Cyclopropylmethoxy-N-(3,5-dichloro-pyridin-4-yl)-4-difluorormethoxy-benzamide(PDE-4 inhibitor Roflumilast);4-[2-(3-cyclopentyloxy-4-methoxyphenyl)-2-phenyl-ethyl]-pyridine (PDE-4inhibitor CDP-840);N-(3,5-dichloro-4-pyridinyl)-4-(difluoromethoxy)-8-[(methylsulfonyl)amino]-1-dibenzofurancarboxamide(PDE-4 inhibitor Oglemilast);N-(3,5-Dichloro-pyridin-4-yl)-2-[1-(4-fluorobenzyl)-5-hydroxy-1H-indol-3-yl]-2-oxo-acetamide(PDE-4 inhibitor AWD 12-281);8-Methoxy-2-trifluoromethyl-quinoline-5-carboxylic acid(3,5-dichloro-1-oxy-pyridin-4-yl)-amide (PDE-4 inhibitor Sch 351591);4-[5-(4-Fluorophenyl)-2-(4-methanesulfinyl-phenyl)-1H-imidazol-4-yl]-pyridine(P38 inhibitor SB-203850);4-[4-(4-(4-Fluoro-phenyl)-1-(3-phenyl-propyl)-5-pyridin-4-yl-1H-imidazol-2-yl]-but-3-yn-1-ol(P38 inhibitor RWJ-67657);4-Cyano-4-(3-cyclopentyloxy-4-methoxy-phenyl)-cyclohexanecarboxylic acid2-diethylamino-ethyl ester (2-diethyl-ethyl ester prodrug of Cilomilast,PDE-4 inhibitor);(3-Chloro-4-fluorophenyl)-[7-methoxy-6-(3-morpholin-4-yl-propoxy)-quinazolin-4-yl]-amine(Gefitinib, EGFR inhibitor); and4-(4-Methyl-piperazin-1-ylmethyl)-N-[4-methyl-3-(4-pyridin-3-yl-pyrimidin-2-ylamino)-phenyl]-benzamide(Imatinib, EGFR inhibitor).

Combinations comprising inhaled β2-adrenoreceptor agonistbronchodilators such as formoterol, albuterol or salmeterol with thecompounds of Formula I-V are also suitable, but non-limiting,combinations useful for the treatment of respiratory viral infections.

Combinations of inhaled β2-adrenoreceptor agonist bronchodilators suchas formoterol or salmeterol with ICS's are also used to treat both thebronchoconstriction and the inflammation (Symbicort® and Advair®,respectively). The combinations comprising these ICS andβ2-adrenoreceptor agonist combinations along with the compounds ofFormula I-V are also suitable, but non-limiting, combinations useful forthe treatment of respiratory viral infections.

For the treatment or prophylaxis of pulmonary broncho-constriction,anticholinergics are of potential use and, therefore, useful as anadditional therapeutic agents in combination with the compounds ofFormula I-V for the treatment of viral respiratory infections. Theseanticholinergics include, but are not limited to, antagonists of themuscarinic receptor (particularly of the M3 subtype) which have showntherapeutic efficacy in man for the control of cholinergic tone in COPD(Witek, 1999);1-{4-Hydroxy-1-[3,3,3-tris-(4-fluoro-phenyl)-propionyl]-pyrrolidine-2-carbonyl}-pyrrolidine-2-carboxylicacid (1-methyl-piperidin-4-ylmethyl)-amide;3-[3-(2-Diethylamino-acetoxy)-2-phenyl-propionyloxy]-8-isopropyl-8-methyl-8-azonia-bicyclo[3.2.1]octane(Ipratropium-N,N-diethylglycinate);1-Cyclohexyl-3,4-dihydro-1H-isoquinoline-2-carboxylic acid1-aza-bicyclo[2.2.2]oct-3-yl ester (Solifenacin);2-Hydroxymethyl-4-methanesulfinyl-2-phenyl-butyric acid1-aza-bicyclo[2.2.2]oct-3-yl ester (Revatropate);2-{1-[2-(2,3-Dihydro-benzofuran-5-yl)-ethyl]-pyrrolidin-3-yl}-2,2-diphenyl-acetamide(Darifenacin); 4-Azepan-1-yl-2,2-diphenyl-butyramide (Buzepide);7-[3-(2-Diethylamino-acetoxy)-2-phenyl-propionyloxy]-9-ethyl-9-methyl-3-oxa-9-azonia-tricyclo[3.3.1.02,4]nonane(Oxitropium-N,N-diethylglycinate);7-[2-(2-Diethylamino-acetoxy)-2,2-di-thiophen-2-yl-acetoxy]-9,9-dimethyl-3-oxa-9-azonia-tricyclo[3.3.1.02,4]nonane(Tiotropium-N,N-diethylglycinate); Dimethylamino-acetic acid2-(3-diisopropylamino-1-phenyl-propyl)-4-methyl-phenyl ester(Tolterodine-N,N-dimethylglycinate);3-[4,4-Bis-(4-fluoro-phenyl)-2-oxo-imidazolidin-1-yl]-1-methyl-1-(2-oxo-2-pyridin-2-yl-ethyl)-pyrrolidinium;1-[1-(3-Fluoro-benzyl)-piperidin-4-yl]-4,4-bis-(4-fluoro-phenyl)-imidazolidin-2-one;1-Cyclooctyl-3-(3-methoxy-1-aza-bicyclo[2.2.2]oct-3-yl)-1-phenyl-prop-2-yn-1-ol;3-[2-(2-Diethylamino-acetoxy)-2,2-di-thiophen-2-yl-acetoxy]-1-(3-phenoxy-propyl)-1-azonia-bicyclo[2.2.2]octane(Aclidinium-N,N-diethylglycinate); or(2-Diethylamino-acetoxy)-di-thiophen-2-yl-acetic acid1-methyl-1-(2-phenoxy-ethyl)-piperidin-4-yl ester.

The compounds of Formula I-V may also be combined with mucolytic agentsto treat both the infection and symptoms of respiratory infections. Anon-limiting example of a mucolytic agent is ambroxol. Similarly, thecompounds of Formula I-V may be combined with expectorants to treat boththe infection and symptoms of respiratory infections. A non-limitingexample of an expectorant is guaifenesin.

It is also possible to combine any compound of the invention with one ormore other active therapeutic agents in a unitary dosage form forsimultaneous or sequential administration to a patient. The combinationtherapy may be administered as a simultaneous or sequential regimen.When administered sequentially, the combination may be administered intwo or more administrations.

Co-administration of a compound of the invention with one or more otheractive therapeutic agents generally refers to simultaneous or sequentialadministration of a compound of the invention and one or more otheractive therapeutic agents, such that therapeutically effective amountsof the compound of the invention and one or more other activetherapeutic agents are both present in the body of the patient.

Co-administration includes administration of unit dosages of thecompounds of the invention before or after administration of unitdosages of one or more other active therapeutic agents, for example,administration of the compounds of the invention within seconds,minutes, or hours of the administration of one or more other activetherapeutic agents. For example, a unit dose of a compound of theinvention can be administered first, followed within seconds or minutesby administration of a unit dose of one or more other active therapeuticagents. Alternatively, a unit dose of one or more other therapeuticagents can be administered first, followed by administration of a unitdose of a compound of the invention within seconds or minutes. In somecases, it may be desirable to administer a unit dose of a compound ofthe invention first, followed, after a period of hours (e.g., 1-12hours), by administration of a unit dose of one or more other activetherapeutic agents. In other cases, it may be desirable to administer aunit dose of one or more other active therapeutic agents first,followed, after a period of hours (e.g., 1-12 hours), by administrationof a unit dose of a compound of the invention.

The combination therapy may provide “synergy” and “synergistic”, i.e.,the effect achieved when the active ingredients used together is greaterthan the sum of the effects that results from using the compoundsseparately. A synergistic effect may be attained when the activeingredients are: (1) co-formulated and administered or deliveredsimultaneously in a combined formulation; (2) delivered by alternationor in parallel as separate formulations; or (3) by some other regimen.When delivered in alternation therapy, a synergistic effect may beattained when the compounds are administered or delivered sequentially,e.g., in separate tablets, pills or capsules, or by different injectionsin separate syringes. In general, during alternation therapy, aneffective dosage of each active ingredient is administered sequentially,i.e., serially, whereas in combination therapy, effective dosages of twoor more active ingredients are administered together. A synergisticanti-viral effect denotes an antiviral effect which is greater than thepredicted purely additive effects of the individual compounds of thecombination.

In still yet another embodiment, the present application provides formethods of inhibiting HCV polymerase in a cell, comprising: contacting acell infected with HCV with an effective amount of a compound of FormulaI-V, or a pharmaceutically acceptable salt, solvate, and/or esterthereof, whereby HCV polymerase is inhibited.

In still yet another embodiment, the present application provides formethods of inhibiting HCV polymerase in a cell, comprising: contacting acell infected with HCV with an effective amount of a compound of FormulaI-V, or a pharmaceutically acceptable salt, solvate, and/or esterthereof, and at least one additional active therapeutic agent, wherebyHCV polymerase is inhibited.

In still yet another embodiment, the present application provides formethods of inhibiting HCV polymerase in a cell, comprising: contacting acell infected with HCV with an effective amount of a compound of FormulaI-V, or a pharmaceutically acceptable salt, solvate, and/or esterthereof, and at least one additional active therapeutic agent selectedfrom the group consisting of interferons, ribavirin analogs, NS3protease inhibitors, NS5a inhibitors, alpha-glucosidase 1 inhibitors,cyclophilin inhibitors, hepatoprotectants, other nucleoside inhibitorsof HCV, non-nucleoside inhibitors of HCV, and other drugs for treatingHCV.

In still yet another embodiment, the present application provides formethods of treating HCV in a patient, comprising: administering to thepatient a therapeutically effective amount of a compound of Formula I-V,or a pharmaceutically acceptable salt, solvate, and/or ester thereof.

In still yet another embodiment, the present application provides formethods of treating HCV in a patient, comprising: administering to thepatient a therapeutically effective amount of a compound of Formula I-V,or a pharmaceutically acceptable salt, solvate, and/or ester thereof,and at least one additional active therapeutic agent, whereby HCVpolymerase is inhibited.

In still yet another embodiment, the present application provides formethods of treating HCV in a patient, comprising: administering to thepatient a therapeutically effective amount of a compound of Formula I-V,or a pharmaceutically acceptable salt, solvate, and/or ester thereof,and at least one additional active therapeutic agent selected from thegroup consisting of interferons, ribavirin analogs, NS3 proteaseinhibitors, NS5a inhibitors, alpha-glucosidase 1 inhibitors, cyclophilininhibitors, hepatoprotectants, other nucleoside inhibitors of HCV,non-nucleoside inhibitors of HCV, and other drugs for treating HCV.

In still yet another embodiment, the present application provides forthe use of a compound of the present invention, or a pharmaceuticallyacceptable salt, solvate, and/or ester thereof, for the preparation of amedicament for treating an HCV infection in a patient.

Metabolites of the Compounds of the Invention

Also falling within the scope of this invention are the in vivometabolic products of the compounds described herein, to the extent suchproducts are novel and unobvious over the prior art. Such products mayresult, for example, from the oxidation, reduction, hydrolysis,amidation, esterification and the like of the administered compound,primarily due to enzymatic processes. Accordingly, the inventionincludes novel and unobvious compounds produced by a process comprisingcontacting a compound of this invention with a mammal for a period oftime sufficient to yield a metabolic product thereof. Such productstypically are identified by preparing a radiolabelled (e.g., ¹⁴C or ³H)compound of the invention, administering it parenterally in a detectabledose (e.g., greater than about 0.5 mg/kg) to an animal such as rat,mouse, guinea pig, monkey, or to man, allowing sufficient time formetabolism to occur (typically about 30 seconds to 30 hours) andisolating its conversion products from the urine, blood or otherbiological samples. These products are easily isolated since they arelabeled (others are isolated by the use of antibodies capable of bindingepitopes surviving in the metabolite). The metabolite structures aredetermined in conventional fashion, e.g., by MS or NMR analysis. Ingeneral, analysis of metabolites is done in the same way as conventionaldrug metabolism studies well-known to those skilled in the art. Theconversion products, so long as they are not otherwise found in vivo,are useful in diagnostic assays for therapeutic dosing of the compoundsof the invention even if they possess no HCV polymerase inhibitoryactivity of their own.

Recipes and methods for determining stability of compounds in surrogategastrointestinal secretions are known. Compounds are defined herein asstable in the gastrointestinal tract where less than about 50 molepercent of the protected groups are deprotected in surrogate intestinalor gastric juice upon incubation for 1 hour at 37° C. Simply because thecompounds are stable to the gastrointestinal tract does not mean thatthey cannot be hydrolyzed in vivo. The prodrugs of the inventiontypically will be stable in the digestive system but may besubstantially hydrolyzed to the parental drug in the digestive lumen,liver or other metabolic organ, or within cells in general.

EXAMPLES

Certain abbreviations and acronyms are used in describing theexperimental details. Although most of these would be understood by oneskilled in the art, Table 3 contains a list of many of theseabbreviations and acronyms.

TABLE 3 List of abbreviations and acronyms. Abbreviation Meaning Ac₂OAcetic anhydride ACN Acetonitrile AcOH or HOAc Acetic acid AlBN2,2′-azobis(2-methylpropionitrile) Ar Aryl Bn Benzyl bs or br s Broadsinglet Bu Butyl Bz Benzoyl cm Centimeters conc. Concentration d DoubletDABCO 1,4-diazabicyclo[2.2.2]octane DBN 1,5-diazabicyclo[4.3.0]non-5-eneDBU 1,5-diazabicyclo[5.4.0]undec-5-ene DCC Dicyclohexylcarbodiimide DCEDichloroethane DCM Dichloromethane dd Doublet of doublets ddd Doublet ofdoublets of doublets DMAP 4-dimethylaminopyridine DMEM Dulbecco'smodified Eagle's medium DMF Dimethylformamide DMSO Dimethylsulfoxide dtDouble triplet DTT Dithiothreitol EDTA Ethylenediaminetetraacetic acidequiv. Equivalents Et Ethyl EtOAc Ethyl acetate FBS Fetal bovine serum gGram h or hr Hour Hex Hexane or Hexanes HPLC High pressure liquidchromatography IBX 2-Iodoxybenzoic acid IPA Isopropyl alcohol kgKilogram LC/MS liquid chromatography/mass spectrometry m Meter m/z orm/e Mass to charge ratio MDCK Madin-Darby Canine Kidney Cells Me MethylMeCN Acetonitrile MeOH Methanol mg Milligram MH⁻ Mass minus 1 MH⁺ Massplus 1 MHz Megahertz min Minute mL Milliliter mmol Millimole MS or msMass spectrum Ms-Cl Methane sulfonyl chloride N Normal NBSN-bromosuccinimide NMP N-methylpyrrolidinone NMR Nuclear magneticresonance PBS Phosphate buffered saline PEG Polyethylene glycol PhPhenyl ppm Parts per million Pyr or Py Pyridine q Quartet RP Reversephase RPMI Roswell Park Memorial Institute rt or r.t. or RT Roomtemperature s Singlet sat. Saturated t Triplet TBAF Tetrabutylammoniumfluoride TBDMS tert-butyldimethylsilyl TEA Triethylamine TESTriethylsilane Tf Trifluoromethanesulfonate TFA Trifluoroacetic acid THFTetrahydrofuran TIPDS-Cl 1,3-dichloro-1,1,3,3-tetraisopropoxy TLC or tlcThin layer chromatography TMS Trimethylsilane TMSOTf(trimethylsilyl)trifluoromethylsulfonate Tr Triphenylmethyl or tritylXTT {2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide} δ parts per milliondown field from tetramethylsilane

Preparation of Compounds

General method for the preparation of 1′-CN substituted nucleosides

The 1′-CN substituted nucleoside (Compound G-C) can be prepared byfollowing a method similar to that described in Tetrahedron Letters,1993, 8579. Accordingly, an appropriately protected 1′-bromo-1′-cyanohexose (Compound G-B), which is obtained from a reaction of thecorresponding 1′-cyano hexose (Compound G-A) with a brominating agentsuch as NBS, is coupled to a silylated pyrimidine base with or without aLewis acid such as tine tetrachloride, mercuric cyanide, or silvertriflate. The coupled product is then de-protected to obtain a 1′-CNsubstituted nucleoside (Compound G-C, Scheme 1). References forpreparation of each individual Compound G-A are cited in the Examplessection below.

General method for the preparation of 1′-alkenyl, 1′-haloethenyl or1′-alkynyl substituted nucleosides

The 1′-alkenyl, 1′-haloethenyl, or 1′-alkynyl substituted nucleoside canbe prepared following a method similar to that described in Journal ofOrganic Chemistry, 2004, 1831. Accordingly, an appropriately protected1′,2′-unsaturated uridine nucleoside (Compound G-D) is converted to the1′,2′-epoxide (Compound G-E), which is reacted with an appropriatetri(alkenyl), tri(haloethenyl) or tri(alkynyl)aluminum to afford an1′-alkenyl, 1′-haloethenyl, or alkynyl substituted uridine nucleoside(Compound G-F) (Scheme 2A). The uridine analog can be converted to thecorresponding cytidine analog (Compound G-G) following general methodswell-established in the practice of nucleoside chemistry, some of whichdetailed procedures are described in the Examples section below (Scheme2B).

Preparation of Exemplary Compounds Compound 1

Compound 1a (prepared according to J. Organic Chemistry, 1968, 2490) wassubjected to the reaction conditions similar to those described inWO200512308, affording Compound 1b (Yield; 74%). Melting point; 101-103°C.

Compound 1b was subjected to the reaction conditions similar to thosedescribed in Tetrahedron Letters, 1993, 8579, affording Compound 1c.Melting point; 44-49° C.

Compound 1c (300 mg, 0.53 mmol) was placed into a microwave vial underargon and dissolved with a 1:1 mixture of anhydrous dichloroethane andacetonitrile (12 mL). 2,6-Lutidine (0.3 mL, 2.6 mmol) was added,followed by 0.3 mL bis-TMS uracil. Then, 300 mg (1.17 mmol) Ag(OTf) wasadded and the mixture was sealed, and heated to 150° C. for 30 minutesvia use of a microwave reactor. After this time, the reaction was judgedcomplete by LC/MS analysis. The reaction was filtered, and the filtratediluted with 300 mL DCM. The organic layer was washed with 300 mLsaturated sodium bicarbonate solution, then 2×300 mL H₂O, and then with300 mL sat. brine solution. The organic phase was dried by passagethrough a hydrophobic membrane filter and the volatiles removed to give330 mg crude product. Chromatography using a 40 g silica column and agradient of 7:3 hexanes/EtOAc to 100% EtOAc gave 90 mg 1d (28% yield) asa single isomer. ¹H-NMR (400 MHz, CD₃CN): □δ 9.30 (bs, 1H), 8.15 (m,1H), 8.08 (m, 2H), 7.78 (d, J=8.4 Hz, 2H), 7.65 (m, 2H), 7.58 (m, 4H),7.25 (m, 2H), 5.92 (d, J=2.8 Hz, 1H), 5.72 (d, J=8.4 Hz, 1H), 4.98 (m,1H), 4.87 (m, 2H), 1.68 (s, 3H). MS=596 (M+H⁺). LC/MS retention time ona 3.5 minute LC/MS method (Polar RP column)=2.48 min.

To a solution of Compound 1d (40 mg, 0.07 mmol) in MeOH (1 mL) at roomtemperature was added 2 mL conc. aq. ammonia. The reaction mixture wasstirred at room temperature for 20 h. LC/MS analysis indicated that thereaction had gone to completion. The reaction was concentrated to aresidue and the crude product, 40 mg, was dissolved in water, andpurified via revered phase HPLC. Concentration of the product fractionsfurnished 14 mg (74% yield) of tris-debenzoylated product Compound 1.¹H-NMR (400 MHz, D₂O): □δ 7.91 (d, J=8.4 Hz, 1H), 5.78 (d, J=8.4 Hz,1H), 4.15 (m, 1H), 3.94 (m, 1H), 3.75 (m, 1H), 3.67 (m, 1H), 1.18 (s,3H). MS=282 (M−H₊). LC/MS retention time on a 3.5 minute LC/MS method(Polar RP column)=0.52 min.

Compound 2

To a solution of Compound 1c (250 mg, 0.4 mmol) in pyridine (8 mL) at 0°C. was added 0.5 g (2 mmol, 5 equiv) 4-Cl-phenyl phosphorodichloridate,followed by 350 mg (5 mmol, 12.5 equiv) 1,2,4-triazole. The reaction wasallowed to warm to rt and stir for an additional 3 h. LC/MS analysisindicated that the reaction had gone to completion. The reaction wasconcentrated to a residue, dissolved in 100 mL DCM, washed with 2×50 mLwater, 50 mL 50% saturated NaHCO₃ aq. solution, followed by drying andconcentration to give 340 mg of the crude intermediate product.

175 mg of the crude residue was taken up in 10 mL of a 1:3 mixture ofconc. aq. NH₄OH and dioxane. The reaction was stirred for 5 h, at whichtime the solvent was removed and the residue azeotroped with toluene togive 160 mg intermediate product. At this time, 10 mL of 7N NH₃ inmethanol was added and the resulting solution stirred for 18 h. LC/MSshowed that the reaction had gone to completion, and the resultingmaterial was purified via reversed phase HPLC. Concentration of theproduct fractions furnished 23 mg (28% overall yield) oftris-debenzoylated product Compound 2. ¹H-NMR (400 MHz, D₂O): □ δ 7.74(d, J=8.0 Hz, 1H), 5.84 (d, J=8.0 Hz, 1H), 4.20 (m, 1H), 3.81 (m, 1H),3.68 (m, 1H), 3.62 (m, 1H), 1.08 (s, 3H). MS=281 (M−H⁺). LC/MS retentiontime on a 3.5 minute LC/MS method (Polar RP column)=0.37 min.

Compound 3

Compound 3a (prepared according to Tetrahedron Letters, 1993, 8579; 16.4g, 30 mmol) was dissolved in 75 mL of each DCE and ACN in a 400 mL highpressure vessel. To this was added Bis(TMS)uracil (12 g, 47 mmol) assolid and lastly Ag(OTf) (11 g, 43 mmol) was added. The reaction wassealed and heated at 135° C. for 90 minutes. The reaction mixture wasthen cooled to rt and precipitous AgBr filtered off. Solvents were thenremoved under vacuum and resulting residue was redissolved in EtOAc andaq. NaHCO₃. Resulting mixture was extracted 3× with EtOAc, then organicswere washed with water (1×), aq. sodium bicarbonate (2×), water (2×) andbrine (1×) before drying over sodium sulfate. The solution was thenfiltered and evaporated to dryness. The residue was purified by silicagel chromatography with Hex:EtOAc to afford 3b (12.8 g; yield 74%). MS[M+H⁺]=581.9. ¹H NMR: (400 MHz, CD₃OD) δ 8.15 (1H, d, J=8.4 Hz), 5.68(1H, d, J=8.4 Hz), 4.52 (1H, d), 4.26 (1H, m), 4.06 (1H, dd), 3.97 (1H,dd, J=12.8, 2.0 Hz), 3.73 (1H, dd, J=12.8, 2.0 Hz). MS [M−H⁺]=268.0.

Compound 3b was converted to Compound 3 in a way similar to preparationof Compound 1.

Compound 4

To a stirring solution of Compound 3b (2 g, 3.44 mmol) in ACN (100 mL)was added TEA (0.96 mL, 6.88 mmol) and then 2,4,6triisopropylbenzenesulfonyl chloride (2.08 g, 6.88 mmol). Lastly wasadded DMAP (840 mg, 6.88 mmol) and the reaction was allowed to stir atroom temperature under argon overnight. Next day, the reaction wasdetermined to be complete by LCMS and the solvents were removed underreduced pressure. The crude was then aminated followed byde-benzoylated, following the procedure described in preparation ofCompound 2. The resulting crude product was dissolved in water andpurified by prep HPLC to give Compound 4 (330 mg, 36% yield). MS[M−H⁺]=267.0. ¹H NMR: (400 MHz, D₂O) δ 7.84 (1H, d, J=7.6 Hz), 5.91 (1H,d, J=7.6 Hz), 4.44 (1H, d), 4.26 (1H, m), 3.96 (1H, dd), 3.88 (1H, dd,J=12.8, 2.0 Hz), 3.67 (1H, dd, J=12.8, 2.0 Hz). MS [M−H⁺]=267.0.

Compound 5

Compound 5 was prepared in a matter similar to that of Compound 3substituting bis(TMS) 5-F uracil for bis(TMS) 5-unsubstituted uracil.

¹H NMR: (400 MHz, D₂O) δ 8.16 (1H, d, J=7.2 Hz), 4.15 (1H, m), 3.95 (1H,dd, J=12.8, 2.4 Hz), 3.73 (1H, dd, J=12.8, 2.4 Hz), 3.69 (1H, d, J=8.8Hz), 1.19 (3H, s). ¹⁹F NMR: (376 MHz, D₂O) δ−165.4 ppm.

LC/MS: m/z (M−H)⁻=300, rt=0.67 min on a 3.5 min C18 HPLC method.

Compound 6

Compound 6 was prepared in a similar way to prepare Compound 4. ¹H NMR(400 MHz, CD₃OD) δ 8.47 (d, J=7.5 Hz, 1H), 4.15 (dt, J=8.5, 2.5 Hz, 1H),4.01 (dd, J=12.8, 2.3 Hz, 1H), 3.80 (dd, J=12.8, 2.6 Hz, 1H), 3.73 (t,J=9.4 Hz, 1H), 1.24 (s, 3H). MS=301 (M+H⁺). LC/MS retention time on a3.5 minute LC/MS method (Polar RP column)=0.50 min.

Compound 7

Concentrated sulfuric acid (0.7 mL) was added to a solution (cloudy) ofCompound 3 (2.57 g, 9.5 mmol) in acetone (70 mL). The resulting solution(clear) was stirred at room temperature for 3 hours. The reaction wasneutralized with triethylamine (3.5 mL) and the solvent was removedunder reduced pressure. The resulting yellow oil was subjected to silicagel chromatography with an eluent of (20% methanol in dichloromethane)and dichloromethane at a gradient of 0-100%. The product containingfractions were combined and the solvent was removed under reducedpressure providing Compound 7a (2.13 g, 72%).

2-Iodoxybenzoic acid (IBX) (3 g, 4.8 mmol, 45% wt) was stirred withethyl acetate (15 mL) for 15 minutes until a smooth mixture formed. Thesolid was isolated by suction filtration and then added to a solution ofCompound 7a (500 mg, 1.6 mmol) in acetonitrile (20 mL). The mixture washeated at 80° C. for 30 min. The reaction mixture was cooled in an icebath and the mother liquor was isolated by suction filtration. Thesolvent was removed under reduced pressure, and the white solid wasazeotroped with toluene. The material Compound 7b was used immediately,and the yield was assumed to be 100%.

A solution of methylmagnesium bromide (2.69 mL, 8.1 mmol, 3M in diethylether) was added to a solution of Compound 7b (495 mg, 1.6 mmol) intetrahydrofuran (20 mL) at −20° C. under an atmosphere of argon. After 5minutes, the mixture was allowed to warm to room temperature. After 45minutes, the mixture was cooled to 0° C. and the reaction was quenchedwith saturated ammonium chloride (10 mL). The tetrahydrofuran wasremoved under reduced pressure and the aqueous phase was extracted withethyl acetate (3×25 mL). The combined organic phases were dried oversodium sulfate and filtered. The solvent was removed under reducedpressure. The resulting residue was subjected to reverse phase HPLC withan eluent of water and acetonitrile. The product containing fractionswere combined and the solvent was removed by lyophilization providingCompound (R)-7c (35 mg, 7%) and Compound (S)-7c (15 mg, 3%).

A solution of Compound (S)-7c (15 mg, 0.046 mmol) and trifluoroaceticacid (1 mL) in water (1 mL) was stirred at room temperature for 5.5hours. The solution was diluted with water (5 mL) and acetonitrile (5mL), and the solvent was removed by lyophilization. The resultingresidue was subjected to reverse phase HPLC with an eluent of water andacetonitrile. The product containing fractions were combined and thesolvent was removed by lyophilization, providing Compound 7 (4.2 mg,32%). ¹H-NMR (400 MHz, D₂O): □δ 8.15 (d, J=8.4 Hz, 1H), 5.59 (d, J=8.4Hz, 1H), 4.42 (d, J=4.4 Hzm 1H), 4.00 (dd, J₁=2.8 Hz, J₂=8.8 Hz, 1H),3.94 (dd, J₁=4.0 Hz, J₂=8.4 Hz, 1H), 3.85 (dd, J=2.4 Hz, J₂=6.4 Hz, 1H),1.27 (d, J=6.4 Hz, 3H). MS=281.8 (M LC/MS retention time on a 6.0 minuteLC/MS method (Polar RP column)=0.33 min.

Compound 8

Compound 8a (prepared by a method reported on Journal of MedicinalChemistry, 2000, 43, 2566; 1.0 g, 2.06 mmol) was dissolved innitromethane (20 mL) at room temperature. TMS-cyanide (296 mg, 2.97mmol) was added followed by BF₃ etherate (0.246 mL). Stirring at roomtemperature was continued. After 45 minutes, the volatiles were removedin vacuo. The crude material was taken into DCM and the solution waswashed with aqueous saturated sodium bicarbonate solution. The organiclayer was dried over sodium sulfate. Filtration and evaporation ofsolvents yielded the crude material Compound 8b (923 mg), which was usedin the next step without further purification. ¹H-NMR (400 MHz, CDCl₃):□ δ 8.08 (m, 2H), 7.92 (m, 4H), 7.57 (m, 3H), 7.43-7.35 (m, 6H),6.00-5.93 (m, 2H), 5.51 (m, 1H), 4.94 (d, J=4.4 Hz, 1H), 4.53 (m, 1H),1.52 (d, J=6.8 Hz, 3H) ppm. LC/MS retention time on a 6.0 minute LC/MSmethod (Polar RP column)=4.87 min.

Compound 8b (923 mg, 1.90 mmol) was subjected to the reaction conditionssimilar to those described in Tetrahedron Letters, 1993, 8579, affordingCompound 8c (768.0 mg, 1.36 mmol). Compound 8c was obtained as a mixtureof two isomers. ¹H-NMR (400 MHz, CDCl₃): □ δ 8.10-7.88 (m, 6H),7.62-7.34 (m, 9H), 6.33-6.26 (m, 1H), 6.10 & 5.90 (m, 1H), 5.58 (m, 1H),4.81-4.75 (m, 1H), 1.56 & 1.52 (d, J=6.8 Hz, 3H) ppm. LC/MS retentiontime on a 6.0 minute LC/MS method (Polar RP column)=5.14 min.

Compound 8c (703 mg, 1.24 mmol), bis-TMS uracil (630 mg, 2.46 mmol), andsilver(I)triflate (630 mg, 2.46 mmol) were placed into a microwave vialunder argon, and anhydrous dichloroethane (5 mL) and acetonitrile (5 mL)were added. The mixture was heated at 135° C. for 30 minutes via use ofa microwave reactor. The reaction mixture was cooled to roomtemperature, filtered, and the volatiles were removed in vacuo. Thecrude material was purified via chromatography on silica gel (eluent:hexanes/EtOAc) affording Compound 8d (504 mg, 0.845 mmol) as a singleisomer. ¹H-NMR (400 MHz, CDCl₃): □ δ 8.08 (d, J=7.2 Hz, 2H), 8.03-8.00(m, 4H), 7.62-7.37 (m, 10H), 6.36 (d, J=5.6 Hz, 1H), 6.11 (m, 1H), 5.66(dq, J=7.2/2.8 Hz, 1H), 4.50 (dd, J=8.4/2.4 Hz, 1H), 4.90 (m, 1H), 1.57(d, J=6.8 Hz, 3H) ppm. MS=596 (M+H⁺). LC/MS retention time on a 6 minuteLC/MS method (Polar RP column)=4.43 min.

To a solution of Compound 8d (65 mg, 0.109 mmol) in MeOH (1 mL) at roomtemperature was added 2 mL conc. aq. ammonia. The reaction mixture wasstirred at room temperature for 8 h. LC/MS analysis indicated thatalmost all the starting material was consumed. The reaction wasconcentrated in vacuo. The crude reaction product was dissolved inwater, and purified via reverse phase HPLC (eluent: water/MeCN). Theproduct containing fractions were combined, frozen, and lyophilized toafford Compound 8 (22.0 mg, 0.077 mmol). ¹H-NMR (400 MHz, D₂O): □δ 7.93(d, J=8.4 Hz, 1H), 5.75 (d, J=8.4 Hz, 1H), 4.50 (m, 1H), 4.15 (m, 3H),1.16 (d, J=6.8 Hz, 3H) ppm. MS=282 (M−H⁺). LC/MS retention time on a 6minute LC/MS method (Polar RP column)=0.97 min.

Compound 9

2,4,6-Triisopropylbenzene-1-sulfonyl chloride (1.58 g, 5.2 mmol) wasadded to a solution of Compound 8d (1.56 g, 2.6 mmol),N,N-dimethylaminopyridine (640 mg, 5.2 mmol) and triethylamine (0.73 mL,5.2 mmol) in acetonitrile (30 ml) and stirred at room temperature for 30minutes. Concentrated aqueous ammonium hydroxide (6 mL) was added andafter 15 minutes the acetonitrile was removed under reduced pressure.The residue was taken up in ethyl acetate (75 mL) and washed with water(20 mL), saturated ammonium chloride (20 mL), and then brine (20 mL).The organic phase was dried over sodium sulfate and filtered. Thesolvent was removed under reduced pressure and the residue was subjectedto silica gel chromatography with an eluent of methanol anddichloromethane. The product containing fractions were combined and thesolvent was removed under pressure to provide Compound 9a (920 mg, 60%).

Concentrated ammonium hydroxide (30 mL) was added to a solution ofCompound 9a (460 mg, 7.7 mmol) in 1,4-dioxane (15 mL). The solution wasstirred at 50° C. in a sealed vessel. After 9 hours, the solution wascooled and the solvent was concentrated to a volume of 10 mL. Themixture was cooled at 0° C. for 5 min and filtered. The filtrate wassubjected to reverse phase HPLC with an eluent of water andacetonitrile. The product containing fractions were combined. Thesolvent was removed by lyophilization to provide Compound 9 (148 mg,67%). ¹H-NMR (400 MHz, D₂O): □ δ 7.88 (d, J=7.6 Hz, 1H), 5.91 (d, J=8.0Hz, 1H), 4.42 (d, J=5.2 Hz, 1H), 4.16 (m, 1H), 4.09 (m, 2H), 1.16 (d,J=7.2 Hz, 3H). MS=283.1 (M+H⁺). LC/MS retention time on a 6.0 minuteLC/MS method (Polar RP column)=0.28 min.

Compound 10

To a solution of Compound 8d (4.32 g, 7.25 mmol) in pyridine/glacialacid (55 mL/13.5 mL) at room temperature was added hydrazine hydrate(598 mg, 10.87 mmol). The reaction mixture was stirred at roomtemperature for 40 hours. Acetone (4 mL) was added and stirring at roomtemperature was continued. After 2 additional hours, the solvent volumewas reduced in vacuo to ˜1/3 of the original volume. The mixture wasdiluted with EtOAc, washed with aqueous HCl (1N) and aqueous saturatedsodium bicarbonate solution/brine (1/1). The organic layer was driedover sodium sulfate. Filtration and evaporation of solvents affordedcrude Compound 10a (3.33 g, 6.77 mmol). The material was used in thenext step without further purification. ¹H-NMR (400 MHz, CDCl₃): □δ 8.43(m, 1H), 8.17 (d, J=6.8 Hz, 2H), 7.86 (d, J=7.6 Hz, 2H), 7.61-7.41 (m,7H), 6.04 (dd, J=5.2/1.2 Hz, 1H), 5.63 (m, 2H), 4.99 (s, 1H), 4.94 (m,1H), 4.79 (m, 1H), 1.54 (d, J=6.8 Hz, 3H) ppm. MS=489 (M−H⁺). LC/MSretention time on a 6 minute LC/MS method (Polar RP column)=3.53 min.

To a solution of Compound 10a (3.25 g, 6.61 mmol) in pyridine (40 mL) atroom temperature was added methanesulfonyl chloride (1.51 g, 13.22mmol). The reaction mixture was stirred at room temperature. After 3hours, more methylsulfonylchloride (0.75 g, 6.61 mmol) was added andstirring at room temperature was continued. After 5 hours, the volatileswere removed in vacuo. The crude reaction mixture was diluted withEtOAc, washed with aqueous HCl (1N), and aqueous saturated sodiumbicarbonate solution/brine (1/1). The organic layer was dried oversodium sulfate. Filtration and evaporation of solvents afforded crudematerial which was purified by chromatography on silica gel (eluent:EtOAc/hexanes) to afford Compound 10b (2.53 g, 4.27 mmol). ¹H-NMR (400MHz, CDCl₃): □δ 9.22 (m, 1H), 8.07 (d, J=7.6 Hz, 2H), 7.95 (d, J=7.2 Hz,2H), 7.61 (m, 2H), 7.47-7.39 (m, 5H), 5.81-5.72 (m, 3H), 5.29 (d,d,J=8.4/1.6 Hz, 1H), 4.87 (dd, J=9.2/3.2 Hz, 1H), 3.36 (s, 3H), 1.45 (d,J=7.2 Hz, 3H) ppm. MS=570 (M+H⁺). LC/MS retention time on a 6 minuteLC/MS method (Polar RP column)=3.84 min.

To a solution of Compound 10b (2.45 g, 4.30 mmol) in acetonitrile (40mL) at room temperature was added triethylamine (2.45 g, 24.20 mmol).The reaction mixture was heated at 65° C. (oil bath). After 2 hours, thereaction was cooled to room temperature and the volatiles were removedin vacuo. The crude reaction mixture was diluted with EtOAc, and washedwith aqueous HCl (1N) and aqueous saturated sodium bicarbonatesolution/brine (1/1). The organic layer was dried over sodium sulfate.Filtration and evaporation of solvents afforded product Compound 10c(1.78 g, 3.76 mmol). ¹H-NMR (400 MHz, CDCl₃): □δ 8.07 (d, J=7.2 Hz, 2H),7.92 (d, J=7.2 Hz, 2H), 7.69-7.37 (m, 7H), 6.01 (d, J=7.6 Hz, 1H), 5.91(m, 1H), 5.78 (d, J=0.8 Hz, 1H), 5.43 (m, 1H), 4.81 (m, 1H), 1.40 (d,J=6.4 Hz, 3H) ppm. MS=472 (M−H⁺). LC/MS retention time on a 6 minuteLC/MS method (Polar RP column)=4.09 min.

To a solution of Compound 10c (1.70 g, 3.59 mmol) in DMF (10 mL) wasadded aqueous HCl (1N, 10 mL) at room temperature. To the resultantsuspension was added more DMF (10 mL). The reaction mixture was heatedat 40° C. (oil bath). After 30 minutes, the reaction was cooled to roomtemperature, diluted with EtOAc, and washed with brine, aqueous LiCl(5%) and aqueous saturated sodium bicarbonate solution/brine (1/1). Theorganic layer was dried over sodium sulfate. Filtration and evaporationof solvents afforded crude reaction mixture which was purified viachromatography on silica gel (eluent: EtOAc/hexanes) to afford theproduct Compound 10d (1.65 g, 3.37 mmol).

¹H-NMR (400 MHz, CDCl₃): □δ 10.08 (s, 1H), 8.13 (d, J=7.2 Hz, 2H), 8.07(d, J=7.2 Hz, 2H), 7.57-7.37 (m, 7H), 5.77 (m, 1H), 5.71 (m, 1H), 5.13(s, 1H), 5.04 (s, 1H), 4.79 (d,d, J=8.4/1.6 Hz, 1H), 4.59 (m, 1H), 1.52(d, J=6.8 Hz, 3H) ppm. MS=492 (M−H⁺). LC/MS retention time on a 6 minuteLC/MS method (Polar RP column)=3.71 min.

To a solution of Compound 10d (65.2 mg, 0.132 mmol) in MeOH (1 mL) atroom temperature was added 2 mL conc. aq. ammonia. The reaction mixturewas stirred at room temperature for 12 hours. The reaction wasconcentrated in vacuo. The crude reaction product was dissolved inwater, and purified via reverse phase HPLC (eluent: water/MeCN). Theproduct containing fractions were combined, frozen, and lyophilized toafford Compound 10 (10.3 mg, 0.036 mmol). ¹H-NMR (400 MHz, D₂O): □δ 7.74(d, J=8.4 Hz, 1H), 5.76 (d, J=8.4 Hz, 1H), 4.69 (m, 1H), 4.26 (m, 1H),4.13 (m, 1H), 3.99 (m, 1H), 1.17 (d, J=6.4 Hz, 3H) ppm. MS=284 (M+H⁺).LC/MS retention time on a 6 minute LC/MS method (Polar RP column)=1.37min.

Compound 11

To a solution of Compound 10d (189.2 mg, 0.385 mmol) in pyridine (2 mL)at room temperature was added acetic anhydride (47.5 mg, 0.462 mmol).After 2 hours, the volatiles were removed in vacuo. The crude reactionmixture was diluted with EtOAc and washed with aqueous HCl (1N) andaqueous saturated sodium bicarbonate solution/brine (1/1). The organiclayer was dried over sodium sulfate. Filtration and evaporation ofsolvents afforded crude material which was purified by chromatography onsilica gel (eluent: EtOAc/hexanes) to afford Compound 11a (185.5 mg,0.348 mmol). ¹H-NMR (400 MHz, CDCl₃): □δ 8.15 (m, 3H), 8.04 (d, J=7.6Hz, 2H), 7.65-7.44 (m, 7H), 5.99 (s, 1H), 5.81-5.73 (m, 3H), 4.69 (m,1H), 1.57-1.54 (m, 6H) ppm. MS=533 (M+H⁺). LC/MS retention time on a 6minute LC/MS method (Polar RP column)=3.89 min.

To a solution of Compound 11a (180.0 mg, 0.338 mmol), DMAP (82.4 mg,0.676 mmol), and triethylamine (68.2 mg, 0.676 mmol) in acetonitrile (8mL) at room temperature was added triisopropylphenylsulfonylchloride(204 mg, 0.676 mmol). Stirring at room temperature was continued. After30 minutes, the reaction was cooled to 0° C. Aqueous concentrated NH₃solution (2 mL) was added and the reaction was allowed to warm to roomtemperature. After additional 30 minutes, the reaction mixture volumewas reduced in vacuo. The crude reaction mixture was diluted with EtOAcand washed with aqueous HCl (1N) and aqueous saturated sodiumbicarbonate solution/brine (1/1). The organic layer was dried oversodium sulfate. Filtration and evaporation of solvents afforded crudematerial which was purified by chromatography on silica gel (eluent:EtOAc/hexanes) to afford a mixture of Compound 11b and its 20′des-acetyl derivative (128.5 mg, combined). This mixture was used in thenext reaction. LC/MS retention time on a 6 minute LC/MS method (Polar RPcolumn)=3.59 min (Compound 11b) and 3.42 min (des-Ac).

To a solution of Compound 11b and its des-acetyl derivative (11.0 mg,˜0.230 mmol) in dioxane (1 mL) at room temperature was added 2 mL conc.aq. ammonia. The reaction mixture was stirred at room temperature for1.5 hours and at 50° C. for 6 hours. The reaction was cooled to roomtemperature and concentrated in vacuo. The crude reaction product wasdissolved in water, and purified via reverse phase HPLC (eluent:water/MeCN). The product containing fractions were combined, frozen, andlyophilized to afford Compound 11 (22.7 mg, 0.081 mmol). ¹H-NMR (400MHz, D₂O): □δ 7.68 (d, J=7.6 Hz, 1H), 5.91 (d, J=7.6 Hz, 1H), 4.70 (s,1H), 4.23 (m, 1H), 4.10 (m, 1H), 3.98 (m, 1H), 1.17 (d, J=6.4 Hz, 3H)ppm. MS=283 (M+H⁺). LC/MS retention time on a 6 minute LC/MS method(Polar RP column)=0.62 min.

Compound 12

Compound 3 (2.0 g, 7.4 mmol) was dissolved in dry pyridine (24 mL). Tothis mixture, 1,3-dichloro-1,1,3,3-tetraisopropyl disiloxane (2 mL. 1.3eq) was added dropwise. The solution was stirred at room temperature for16 hours. The solvent was then removed under vacuum and the resultingresidue was dissolved in EtOAc, washed with H₂O and brine. The organicphase was dried over Na₂SO₄ and evaporated to dryness. The crude productwas purified by column chromatography on silica gel using ethylacetate/hexanes to give Compound 12a (2.1 g, 55% yield). MS=510 (M−H⁺).LC/MS retention time on a 3.5 minute LC/MS method (Polar RP column)=2.49min.

Triethylamine (0.089 mL, 0.64 mmol) was added to a stirring solution ofCompound 12a (300 mg, 0.49 mmol) in CH₃CN (5 mL).2,4,6-Triisopropylbenzenesulfonyl chloride (192 mg, 0.64 mmol) and4-dimethylaminopyridine (78 mg, 0.64 mmol) were added. The reactionmixture was stirred at room temperature for 1 hour. Ethanol (25 mL) wasadded to the mixture, together with additional triethylamine (0.34 mL).The solution was stirred at room temperature for 5 hours. The solventwas then removed under vacuum and the resulting residue was dissolved inEtOAc, washed with concentrated NH₄Cl, H₂O and brine. The organic phasewas dried over Na₂SO₄ and evaporated to dryness. The crude product waspurified by column chromatography on silica gel using ethylacetate/hexanes to give Compound 12b (250 g, 95% yield). MS=540 (M+H⁺).LC/MS retention time on a 3.5 minute LC/MS method (Polar RP column)=2.69min.

Compound 12b (900 mg, 1.8 mmol) was dissolved in dry acetone (20 mL).Silver (I) oxide (3.3 g, 14 mmol) was added to the solution, followed bythe addition of methyl iodide (2.5 g, 18 mmol). The solution was stirredat room temperature for 16 hours. The mixture was filtered to remove thesuspended oxide, concentrated under vacuum and purified by columnchromatography on silica gel using ethyl acetate/hexanes to giveCompound 12c (250 g, 26% yield). MS=554 (M+H⁺). LC/MS retention time ona 3.5 minute LC/MS method (Polar RP column)=2.75 min.

Compound 12c (220 mg, 0.40 mmol) was dissolved in methanol (6 mL) andthe resulting solution was cooled to 0° C. in an ice bath. Hydrochloricacid (0.6 mL, 1 M in H₂O) was added drop-wise. After the addition wascomplete, the mixture was allowed to warm up to room temperature andstirred for 12 hours. The solvent was concentrated and the residue waswashed twice with DCM to remove silyl impurities. The crude purified bycolumn chromatography on silica gel using MeOH/DCM to give Compound 12(80 mg, 70% yield). MS=284 (M+WI LC/MS retention time on a 3.5 minuteLC/MS method (Polar RP column)=0.90 min.

Compound 13

Compound 12 (70 mg, 0.25 mmol) was dissolved in dry pyridine (2 mL). Tothis mixture, 1,3-dichloro-1,1,3,3-tetraisoporpyl disiloxane (0.10 mL.1.3 eq) was added dropwise. The solution was stirred at room temperaturefor 2 hours. The solvent was then removed under vacuum and the resultingresidue was dissolved in EtOAc, washed with H₂O and brine. The organicphase was dried over Na₂SO₄ and evaporated to dryness. The crude productwas purified by column chromatography on silica gel using ethylacetate/hexanes to give Compound 13a (120 mg, 55% yield). MS=526 (M+H⁺).LC/MS retention time on a 3.5 minute LC/MS method (Polar RP column)=2.57min.

Triethylamine (60 mg, 0.60 mmol) was added to a stirring solution ofCompound 13a (155 mg, 0.30 mmol) in CH₃CN (1 mL).2,4,6-Triisopropylbenzenesulfonyl chloride (179 mg, 0.60 mmol) and4-dimethylaminopyridine (72 mg, 0.0.60 mmol) were added. The reactionmixture was stirred at room temperature for 3 hours. The mixture wasevaporated to dryness. The residue was dissolved in CH₃CN (3 mL), andNH₃ (28% aqueous solution, 6 mL) was added. The reaction mixture wasstirred at room temperature for 2 hours. Then the solvent was removedunder vacuum and the residue was dissolved in CH₂Cl₂ and washed withbrine. The organic phase was dried over Na₂SO₄ and evaporated todryness. The crude product was purified by column chromatography onsilica gel using ethyl acetate/methanol 3:1 to give Compound 13b (80 mg,52% yield). MS=556 (M+H⁺). LC/MS retention time on a 3.5 minute LC/MSmethod (Polar RP column)=2.45 min.

Compound 13b (240 mg, 0.46 mmol) was dissolved in anhydrous THF (6 mL).Tetrabutylammonium difluorodiphenylsilicate (TBAT) was added (540 mg,1.01 mmol) and the resulting solution was stirred at rt for 20 min.Acetic acid (0.06 mL, 1.0 mmol) was added. The mixture was concentratedand the residue was dissolved in water. The insoluble material wasremoved by filtration. The filtrate was purified by HPLC (neutral mode,RP Polar column) to give Compound 13 (30 mg, 24% yield). MS=283 (M+H⁺).¹H NMR (400 MHz, CD₃OD) δ 8.14 (d, J=7.7 Hz, 1H), 5.89 (d, J=7.7 Hz,1H), 4.16 (dd, J=10.1, 4.4 Hz, 2H), 3.80 (s, 3H), 3.73 (dd, J=10.0, 2.5Hz, 1H). LC/MS retention time on a 3.5 minute LC/MS method (Polar RPcolumn)=0.48 min.

Compound 14

To a dry, argon purged round bottom flask (25 mL) was added Compound 1and anhydrous pyridine (4 mL). 1,3-Dichloro-1,1,3,3-tetraisoporpyldisiloxane (1.33 mL, 4.16 mmol) was added dropwise and the reactionstirred for 2 h at 0° C. The ice bath was then removed and the mixturewarmed to room temperature and continued to stir until completedisappearance of the starting material. After 10 mins of warming, thereaction was diluted with 10 mL of H₂O and the desired material wascollected via vacuum filtration. The material was placed under highvacuum overnight for further drying. 1.90 g (96% yield) of the desiredmaterial, Compound 14a, was collected. MS=526.4 (M−H⁺). LC/MS retentiontime on a 6.0 minute LC/MS method (Polar RP column)=5.09 min.

To a dry, argon purged round bottom flask (50 mL) was added Compound 14a(1.7 g, 3.23 mmol), anhydrous dichloromethane (10 mL) and anhydrousacetonitrile (10 mL). Dimethylamino pyridine (1.19 g, 9.7 mmol) was thenadded portionwise followed by dropwise addition of methylchlorooxoacetate (0.89 mL, 9.7 mmol). The reaction was allowed to stirat room temperature until complete disappearance of the startingmaterial. After 1.5 h, the crude reaction mixture was diluted with EtOAcfollowed by washings with NaHCO₃ (sat), water, and brine. The combinedorganic layers were dried over NaSO₄ and the solvent was removed underreduced pressure. The mixture was dried azeotropically using toluene andplaced under high vacuum overnight for completeness. 1.72 g (87% yield)of the desired material, Compound 14b, was collected. ¹H-NMR (400 MHz,CD3OD): □δ 7.82 (d, J=8.4 Hz, 1H), 5.78 (d, J=8.4 Hz, 1H), 4.47 (m, 1H),4.30 (m, 1H), 4.20 (m, 2H), 3.93 (s, 3H), 2.89 (s, 3H), 1.08 (m, 28H).MS=609.8 (M−H⁺). LC/MS retention time on a 6.0 minute LC/MS method(Polar RP column)=5.35 min.

To a dry, argon purged round bottom flask (500 mL) was added Compound14b (1.75 g, 2.86 mmol) and anhydrous toluene (120 mL). AIBN (118.8 g,0.49 mmol) and Bu₃SnH (2.3 mL, 8.78 mmol) were then added and the flaskwas placed into a heating block and set to 100° C. After 3 h, thesolvent was removed under reduced pressure and the crude reactionmixture was purified using flash chromatography (Hex/EtOAc). The desiredmaterial, Compound 14c, was collected, along with alpha isomer (900 mg;62%, 78:22 beta/alpha). Beta-isomer after column separation; ¹H-NMR (400MHz, CD3OD): □δ 7.82 (d, J=8.4 Hz, 1H), 5.73 (d, J=8.4 Hz, 1H), 4.22 (m,2H), 4.09 (m, 2H), 3.15 (m, 1H), 1.01 (m, 31H). MS=507.9 (M−H). LC/MSretention time on a 6.0 minute LC/MS method (Polar RP column)=5.18 min.

To a dry, argon purged round bottom flask (100 mL) was added Compound14c (500 mg, 1.00 mmol) and anhydrous acetonitrile (13 mL).Dimethylamino pyridine (244 mg, 2.0 mmol) and triethylamine (0.28 mL,2.0 mmol) were then added to the flask. Lastly, 2,4,6-triisopropylbenzene sulfonyl chloride (0.28 mL, 2 mmol) was added to the mixture andthe solution turned yellow. The reaction continued to stir at roomtemperature until complete disappearance of the starting material. After45 min, ammonium hydroxide (2.6 mL, 20% by volume) was added at 0° C.and the reaction was allowed to slowly warm to room temperature. Afteran additional 20 min, the solvent was removed under reduced pressure.The crude reaction mixture was diluted with EtOAc followed by washingswith NaHCO₃ (sat), water, and brine. The combined organic layers weredried over NaSO₄ and the solvent was removed under reduced pressure. Thecrude reaction mixture was then purified using flash chromatography(DCM/MeOH). 380 mg (75% yield) of the desired material, Compound 14d,was collected. ¹H-NMR (400 MHz, CD3OD): □δ 7.77 (d, J=8.4 Hz, 1H), 5.93(d, J=8.4 Hz, 1H), 4.23 (m, 2H), 4.07 (m, 2H), 3.17 (m, 1H), 1.25 (m,1H), 1.09 (m, 27H), 0.96 (m, 3H). MS=509.1 (M−H⁺). LC/MS retention timeon a 6.0 minute LC/MS method (Polar RP column)=4.83 min.

To a dry, argon purged round bottom flask (50 mL) was added Compound 14d(180 mg, 0.35 mmol) and anhydrous tetrahydrofuran (9 mL). TBAF (0.23 mL,0.778 mmol) was then added and the reaction was allowed to stir at roomtemperature until complete disappearance of the starting material. After10 min, acetic acid was added to neutralize the solution and then thesolvent was removed under reduced pressure. The crude reaction mixturewas dissolved in water, insolubles filtered, and the filtrate purifiedusing prep HPLC. 80 mg (86%) of the desired material, Compound 14, wascollected.

¹H-NMR (400 MHz, CD3OD): □δ 7.77 (d, J=8.4 Hz, 1H), 5.94 (d, J=8.4 Hz,1H), 4.24 (m, 1H), 3.91 (m, 1H), 3.83 (m, 1H), 3.70 (m, 1H), 3.07 (m,1H), 0.66 (d, J=7.5 Hz, 3H). MS=267.1 (M+H⁺). LC/MS retention time on a3.0 minute LC/MS method (Polar RP column)=0.40 min.

Compound 15

Compound 15 was prepared from Compound 14c under conditions similar tothose described in conversion of Compound 14d to Compound 14.

¹H-NMR (400 MHz, CD3OD): □δ 7.83 (d, J=8.4 Hz, 1H), 5.78 (d, J=8.4 Hz,1H), 4.24 (m, 1H), 3.94 (m, 1H), 3.84 (dd, 1H), 3.71 (dd, 1H), 3.07 (m,1H), 0.76 (d, J=7.5 Hz, 3H). MS=268.1 (M+H⁺). LC/MS retention time on a3.0 minute LC/MS method (Polar RP column)=0.79 min.

Compound 16

Compound 16 may be obtained from Compound 3 following synthetic sequenceshown above, of which procedures are described in Journal of OrganicChemistry, 1981, 46, 3603. Briefly, a solution of Compound 3 and tritylchloride (˜1.1 eq) in pyridine is stirred at room temperature. Ifnecessary, additional trityl chloride is added at about 24 h and about48 h. After the reaction is complete, the solvent is removed and theresidue is partitioned between dichloromethane and water. The organiclayer is concentrated and the residue is purified by silica gelchromatography. The tritylated intermediate is then treated with(thiocarbonyl)diimidazole (˜1.4 eq.) in DMF for about 1 h to 24 h toafford, after usual work-up, the 2′,3′-O-thiocarbonate. A solution ofthe thiocarbonate in toluene is treated with a solution oftri-n-butyltin hydride (3-4 eq.) and a catalytic amount of AlBN intoluene at about 80 to about 120° C. for about 30 min. to 5 hr. Theusual work-up and purification afford the 3′-deoxy product, along with2′-deoxy product. The desired 3′-deoxy intermediate is then treated with80-95% formic acid to afford Compound 16.

Compound 17

Compound 17 is obtained from Compound 16 by following the proceduresimilar to that for preparation of Compound 4.

Compound 18

Compound 18 is prepared by following synthetic sequence similar to thatfor Compound 8 substituting Compound 18a for Compound 8a.

Preparation of 18a

Compound 18a may be obtained by a reaction sequence as shown above.Detailed procedures for construction of the oxetane ring is described inOrganic Biomolecular Chemistry, 2003, 1, 3513. Protection andde-protection in this preparation are achieved by general methodswell-established in the practice of nucleoside chemistry.

Compound 19

Compound 19 is obtained from Compound 18 by following the proceduresimilar to that for preparation of Compound 4.

General method for the preparation of 1′-CN-4′-azido substitutednucleosides

Incorporation of the azido group at the 4′-position of 1′-CN substitutednucleoside consists of dehydration to Compounds G-I from Compounds G-Hand subsequent azido-hydroxylation to G-J (Scheme 3). Compounds G-J areprepared according to methods well established in the art. Relevantreferences include Arch. Pharm. Res., 1995, 364; Antiviral Chemistry andChemotherapy, 2009, 99; Bioorganic and Medicinal Chemistry Letters,2007, 2570; Journal of Medicinal Chemistry, 1992, 1440; Journal ofMedicinal Chemistry, 2007, 5463; Journal of Medicinal Chemistry, 2009,2971; Synlett, 2011, 57; EP371366, 1990.

Compound 20

Compound 20 is prepared according to the general method, starting fromCompound 3.

Compound 21

Compound 21 is prepared according to the general method, starting fromCompound 15.

Compound 22

Compound 22 is prepared starting from Compound 20. The stereochemistryof 2′-alpha-OH is switched to 2′-beta-OH in a matter similar to that ofCompound 10.

Compound 23

Compound 23b is obtained from Compound 23a (prepared according toTetrahedron, 2000, 5363) by a method similar to that described inTetrahedron Letters, 1995, 1683, using di-t-butyl-dichlorosilane andsilver nitrate.

Compound 23c is obtained from Compound 23b by a method similar to thatdescribed in Journal of Organic Chemistry, 2004, 1831, usingdimethyldioxirane and triethynylaluminum.

Compound 23 is obtained from Compound 23c by a method similar to thatdescribed in Tetrahedron Letters, 1995, 1683, using pyridiniumpoly(hydrogen fluoride).

Compound 24

Compound 24 is obtained from Compound 23 by following the proceduresimilar to that for preparation of Compound 4.

Compound 25

Compound 25 is obtained by a manner similar to preparation of Compound23, except using trivinylaluminum instead of triethynylaluminum.

Compound 26

Compound 26 is obtained from Compound 25 by following the proceduresimilar to that for preparation of Compound 4.

General Procedure for Preparation of Nucleotide Triphosphates:

To a pear-shaped flask (5-15 mL) is charged with a nucleoside (˜20 mg).Trimethyl phosphate (0.5-1.0 mL) is added. The solution is cooled withice-water bath. POCl₃ (40-45 mg) is added and stirred at 0° C. until thereaction is complete (1 to 4 h; the reaction progress is monitored byion-exchange HPLC; analytical samples are prepared by taking about 3 μLof the reaction mixture and diluting it with 1.0 M Et₃NH₂CO₃ (30-50μL)). A solution of pyrophosphate-Bu₃N (250 mg) and Bu₃N (90-105 mg) inacetonitrile or DMF (1-1.5 mL) is then added. The mixture is stirred at0° C. for 0.3 to 2.5 h, and then the reaction is quenched with 1.0 MEt₃NH₂CO₃ (˜5 mL). The resulting mixture is stirred for additional 0.5-1h while warming up to room temperature. The mixture is concentrated todryness, re-dissolved in water (4 mL), and purified by ion exchangeHPLC. The fractions containing the desired product is concentrated todryness, dissolved in water (˜5 mL), concentrated to dryness, and againdissolved in water (˜5 mL). NaHCO₃ (30-50 mg) is added and concentratedto dryness. The residue is dissolved in water and concentrated todryness again. This process is repeated 2-5 times. The residue is thensubjected to C-18 HPLC purification, affording the desired product as asodium salt. Alternatively, the crude reaction mixture is subjected toC-18 HPLC first and then ion exchange HPLC purification to afford thedesired product as a triethylammonium salt.

Compound 27

Compound 27 was prepared by the general method using Compound 1 asstarting material. ¹H NMR (400 MHz, D₂O): δ 7.82 (d, 1H), 5.75 (d, 1H),4.1-4.3 (m, 3H), 3.95 (d, 1H), 1.10 (s, 3H). ³¹P NMR (162 MHz, D₂O): δ−5.5 (d), −10.9(d), −21.3(t). MS=522.0 (M−H⁺).

Compound 28

Compound 28 was prepared by the general method using Compound 2 asstarting material. ¹H NMR (400 MHz, D₂O): δ 7.95 (d, 1H), 6.04 (d, 1H),4.1-4.4 (m, 3H), 3.87 (d, 1H), 3.10 (NCH₂CH₃), 1.10 (s, 3H, overlappedwith NCH₂CH₃). ³¹P NMR (162 MHz, D₂O): δ −10.7 (d), −11.5(d), −23.2(t).MS=521.0 (M−H⁺).

General Procedure for Preparation of a Nucleoside Prodrug Type PD-A:

Non-limiting examples of mono-phosphoramidate prodrugs comprising theinstant invention may be prepared according to general Scheme 4.

The general procedure comprises the reaction of an amino acid ester saltCompound 100b, e.g., HCl salt, with an aryl dichlorophosphate Compound100a in the presence of about two to ten equivalents of a suitable baseto give the phosphoramidate Compound 100c. Suitable bases include, butare not limited to, imidazoles, pyridines such as lutidine and DMAP,tertiary amines such as triethylamine and DABCO, and substitutedamidines such as DBN and DBU. Tertiary amines are particularlypreferred. Preferably, the product of each step is used directly in thesubsequent steps without recrystallization or chromatography. Specific,but non-limiting, examples of Compound 100a, Compound 100b, and Compound100c can be found in WO 2006/121820 that is hereby incorporated byreference in its entirety. A Nucleoside reacts with the phosphorouschloridate Compound 100c in the presence of a suitable base. Suitablebases include, but are not limited to, imidazoles, pyridines such aslutidine and DMAP, tertiary amines such as triethylamine and DABCO, andsubstituted amidines such as DBN and DBU. The product Compound PD-A maybe isolated by recrystallization and/or chromatography.

Alternative General Procedure for PD-A

The phosphorous chloridate Compound 100c reacts with an activated phenolsuch as 4-nitrophenol, 2-nitrophenol, and 2,4-dinitrophenol, in thepresence of a suitable base to give a phosphorous phenolate Compound100d that is stable for further purification. Compound 100d is thencoupled with a Nucleoside; a solution of a Nucleoside in NMP (˜30mL/mmol) is cooled to 0° C. using an ice bath. To this mixture, asolution of t-BuMgCl in THF (1.0 M, 1.5-2.5 eq. to the nucleoside) isadded dropwise. A solution of Compound 100d (˜1.5 eq. to the nucleoside)in THF (˜15 mL/mmol) is then added dropwise to the reaction mixture. Theresulting mixture is allowed to warm up to room temperature and stirredfor 16 h. The solution is then quenched with H₂O (˜30 mL/mmol) andpurified via reverse phase HPLC (30-60% CH₃CN in H₂O). The productfractions are combined, concentrated under vacuum, and then furtherpurified using flash silica gel chromatography (1-35% MeOH in CH₂Cl₂) togive a monophosphate prodrug Compound PD-A. The diasteromeric mixture ofCompound 100d is optionally separated into two single stereoisomersCompound (S)-100d and Compound (R)-100d by crystallization orchromatography prior to coupling with the Nucleoside to afford a singlestereoisomer Compound (S)-PD-A or Compound (R)-PD-A.

Compound 29

A solution of Compound 1 (37 mg, 0.13 mmol) in NMP (4 mL) was cooled to0° C. using an ice bath. To this mixture, a solution of t-BuMgCl in THF(0.46 mL, 1.0 M) was added dropwise. A solution of Compound 100d-1 (82mg, 0.20 mmol) in THF (2 mL) was then added dropwise to the reactionmixture. The resulting mixture was allowed to warm up to roomtemperature and stirred for 16 h. The solution was then quenched withH₂O (4 mL) and purified via reverse phase HPLC (30-60% CH₃CN in H₂O).The product fractions were combined, concentrated under vacuum, and thenfurther purified using flash silica gel chromatography (2-35% MeOH inCH₂Cl₂) to give Compound 29 (8 mg, 14%) as a diastereomeric mixture. ¹HNMR (400 MHz, CD₃OD) δ 7.86 (d, J=8.4 Hz, 1H), 7.36 (t, J=7.9 Hz, 2H),7.31-7.14 (m, 3H), 5.62 (d, J=8.4 Hz, 1H), 4.96 (dt, J=12.5, 6.3 Hz,1H), 4.55 (ddd, J=12.2, 6.3, 1.9 Hz, 1H), 4.45-4.24 (m, 2H), 4.08 (q,J=7.1 Hz, 1H), 3.98-3.60 (m, 2H), 1.34 (dd, J=7.1, 0.6 Hz, 3H),1.27-1.17 (m, 9H). ³¹P NMR (162 MHz, CD₃OD) δ −4.16, −4.02. MS=551(M−H⁺). LC/MS retention time on a 3.5 minute LC/MS method (Polar RPcolumn)=1.89 min.

Compound 30

A solution of Compound 2 (40 mg, 0.14 mmol) in NMP (4 mL) was cooled to0° C. using an ice bath. To this mixture, a solution of t-BuMgCl in THF(0.49 mL, 1.0 M) was added dropwise. A solution of Compound (S)-100d-1(86 mg, 0.21 mmol) in THF (2 mL) was then added dropwise to the reactionmixture. The resulting reaction mixture was allowed to warm up to roomtemperature and stirred for 16 h. The solution was then quenched withH₂O (4 mL) and purified via reverse phase HPLC (30-60% CH₃CN in H₂O).The product fractions were combined, concentrated under vacuum, and thenfurther purified using flash silica gel chromatography (2-40% MeOH inCH₂Cl₂) to give Compound (S)-30 (16 mg, 21%). ¹H NMR (400 MHz, CD₃OD) δ7.83 (t, J=9.0 Hz, 1H), 7.35 (t, J=7.9 Hz, 2H), 7.28-7.12 (m, 3H), 5.87(dd, J=12.8, 7.8 Hz, 1H), 4.96 (dt, J=12.6, 6.3 Hz, 1H), 4.64-4.46 (m,1H), 4.35 (ddd, J=11.7, 6.4, 2.9 Hz, 2H), 3.91 (dq, 14.1, 7.1 Hz, 1H),3.66 (d, J=7.7 Hz, 1H), 1.33 (t, J=9.3 Hz, 3H), 1.21 (dd, J=6.2, 2.0 Hz,6H), 1.11 (s, 3H). ³¹P NMR (162 MHz, CD₃OD) δ −4.00. MS=552 (M+H⁺).LC/MS retention time on a 3.5 minute LC/MS method (Polar RP column)=1.80min.

Preparation of Compound (S)-100d-1

Alanine isopropyl ester hydrochloride (7.95 g, 47.4 mmol) was suspendedin dichloromethane (100 mL). Compound 100a (10 g, 47.4 mmol) was added.Triethylamine (13.2 mL, 95 mmol) was then dropwise added over a periodof 15 min. (internal reaction temperature; −10° C. ˜−3° C.). When thereaction was almost complete (by phosphorous NMR), p-nitrophenol (6.29g, 45.0 mmol) was added as a solid in one portion. To the resultingslurry was added triethylamine (6.28 mL, 45 mmol) over a period of 15min. The mixture was then warmed up to room temperature. When thereaction was complete, MTBE (100 mL) was added. The white precipitatewas removed by filtration. The filter cake was washed with MTBE (3×50mL). The filtrate and washings were combined and concentrated. Theresidue was purified by silica gel column chromatography (0 to 50% ethylacetate/hexanes), affording Compound 100d-1 as a 1:1 ratio ofdiasteromeric mixture (14.1 g, 77%). ¹H NMR (300 MHz, CDCl₃): δ 8.22(2d, 2H), 7.2-7.4 (m, 7H), 5.0 (m, 1H), 4.09 (m, 1H), 3.96 (m, 1H), 1.39(2d, 3H), 1.22 (m, 6H). MS=409.0 (M+H⁺), 407.2 (M−H⁺).

Separation of Two Diastereomers of Compound 100d-1

The two diastereomers were separated by chiral column chromatographyunder the following conditions;

Column: Chiralpak IC, 2×25 cm

Solvent system: 70% heptane and 30% isopropanol (IPA)

Flow rate: 6 mL/min.

Loading volume per run: 1.0 mL

Concentration of loading sample: 150 mg/mL in 70% heptane and 30% IPA

Compound (S)-100d-1: retention time 43 min. ³¹P NMR (162.1 MHz, CDCl₃):δ-2.99 (s). Compound (R)-100d-1: retention time 62 min. ³¹P NMR (162.1MHz, CDCl₃): δ-3.02 (s).

Alternatively, the two diastereomers were separated by crystallizationunder the following procedure;

Compound 100d-1 was dissolved in diethyl ether (˜10 mL/gram). Whilestirring, hexanes was then added until the solution became turbid. Seedcrystals (˜10 mg/gram of Compound (S)-100d-1) were added to promotecrystallization. The resulting suspension was gently stirred for 16 h,cooled to ˜0° C., stirred for an additional 2 h, and filtered to collectthe crystalline material (recovery yield of the crystalline material35%-35%). The crystalline material contains ˜95% of Compound (S)-100d-1and ˜5% of Compound (R)-100d-1. Re-crystallization afforded 99%diastereomerically pure (S)-isomer.

Compound 31

A solution of Compound 4 (50 mg, 0.188 mmol) in NMP (5 mL) was cooled to0° C. under argon. To this was added 3.5 eq. of t-BuMgCl dropwise. Tothe resulting suspension was added Compound (S)-100d-1 (218 mg, 0.47mmol) predissolved in THF (3 mL) dropwise. Reaction was then immediatelyheated to 50° C. and reaction progress was monitored for completion byLCMS (45-60 minutes). When reaction was determined to be completereaction was cooled, 0.5 mL of each water and MeOH were added to thereaction, the reaction was filtered, and purified by prep HPLC to affordCompound (S)-31 (43 mg, 43% yield). MS [M+H⁺]=538.9

Compound 32

A solution of Compound 9 (148 mg, 0.52 mmol), p-toluenesulfonic acidmonohydrate (76 mg, 0.40 mmol) and trimethylortho formate (6 mL) in1,4-dioxane (6 mL) was stirred at room temperature for 1.5 h. Thereaction was neutralized with triethylamine (0.06 mL) and the solventwas removed under reduced pressure. The residue was take up in methanol(8 mL) and stirred at room temperature for 30 minutes. The solvent wasremoved under reduced pressure. The residue was subjected to silica gelchromatography with an eluent of methanol and 1% triethylamine indichloromethane. The product containing fractions were combined and thesolvent was removed under pressure to provide Compound PD-9a (143 mg,84%).

A solution of tert-butylmagnesium chloride (0.23 mL, 0.23 mmol 1.0 M) intetrahydrofuran was added to a solution of Compound PD-9a (50 mg, 0.15mmol) in tetrahydrofuran (2 mL) under argon. A white solid formed. After30 minutes, a solution of Compound (S)-100d-1 (126 mg, 0.31 mmol) intetrahydrofuran (1 mL) was added and the mixture was heated to 50° C.After 20 minutes the solid had dissolved and the solution was yellow.The reaction was cooled to 0° C. and quenched with methanol (1 mL). Thesolvent was removed under reduced pressure and the residue was subjectedto silica gel chromatography with an eluent of methanol indichloromethane. The product containing fractions were combined and thesolvent was removed under pressure to provide Compound (S)—PD-9b (76.8mg, 83%).

A solution of Compound (S)-PD-9b (76.8 mg, 0.13 mmol) in formic acid (5mL, 95%) and water (1 mL) was stirred for 20 min. The solvent wasremoved under reduced pressure and the residue was azeotroped with ethylacetate. The resulting residue was subjected to reverse phasechromatography with an eluent of acetonitrile and water. The productcontaining fractions were combined. The solvent was removed bylyophilization to provide Compound (S)-32 (8.3 mg, 31%). ¹H-NMR (400MHz, DMSO): □δ7.92 (d, J=7.6 Hz, 1H), 7.45 (s, 1H), 7.39 (s, 1H), 7.35(t, J=8.0 Hz, 2H), 7.16 (m, 3H), 6.72 (d, J=5.2 Hz, 1H), 6.04 (dd,J₁=10.0 Hz, J₂=13.2 Hz, 1H), 5.68 (d, J=7.6 Hz, 1H), 5.27 (d, J=7.2 HZ,1H), 4.83 (m, 2H), 4.22 (m, 2H), 3.87 (m, 1H), 3.75 (m, 1H), 1.38 (d,J=6.8 Hz, 3H), 1.18 (d, J=6.8 Hz, 3H), 1.11 (m, 6H). ³¹P-NMR (400 MHz,DMSO): □δ 3.22 (s). MS=552.0 (M+H⁺). LC/MS retention time on a 6.0minute LC/MS method (Polar RP column)=2.52 min.

Compound 33

Compound (S)-33 was prepared following the procedure for Compound (S)-32except using Compound 8 as the starting material. ¹H-NMR (400 MHz,DMSO): □δ 11.53 (d, 18 Hz), 7.91 (m, 1H), 7.30 (m, 2H), 7.12 (m, 3H),6.74 (d, J=6.0 HZ, 1H), 5.97 (m, 1H), 5.32 (m, 2H), 4.78 (m, 2H), 4.32(t, J=5.2 Hz, 1H), 3.89 (m, 1H), 3.73 (m, 1H), 1.31 (m, 3H), 1.47 (m,3H), 1.07 (m, 6H). ³¹P-NMR (400 MHz, DMSO): □δ3.52 (s). MS=553.3 (M+H⁺).LC/MS retention time on a 6.0 minute LC/MS method (Polar RP column)=2.76min.

Compound 34

A solution of Compound 12 (10 mg, 0.035 mmol) in NMP (1 mL) was cooledto 0° C. using an ice bath. To this mixture, a solution of t-BuMgCl inTHF (0.12 mL, 1.0 M) was added dropwise. A solution of Compound(S)-100d-1 (22 mg, 0.053 mmol) in THF (1 mL) was then added dropwise tothe reaction mixture. The resulting mixture was allowed to warm up toroom temperature and stirred for 16 h. The solution was then quenchedwith H₂O (2 mL) and purified via reverse phase HPLC (30-60% CH₃CN in H₂Oto give Compound (S)-34 (1 mg, 10%). ¹H NMR (400 MHz, CD₃OD) δ 7.86 (d,J=8.3 Hz, 1H), 7.36 (t, J=7.9 Hz, 2H), 7.28-7.11 (m, 3H), 5.59 (d, J=8.3Hz, 1H), 4.95 (dt, J=12.5, 6.2 Hz, 1H), 4.52 (dd, J=10.8, 5.9 Hz, 1H),4.42-4.21 (m, 2H), 4.02 (dd, J=9.7, 4.9 Hz, 1H), 3.89 (dt, J=17.4, 7.3Hz, 1H), 3.78 (s, 3H), 1.41-1.12 (m, 10H). MS=553 (M+H⁺). ³¹P NMR (162.1MHz, CDOD): δ 4.03 (s). LC/MS retention time on a 3.5 minute LC/MSmethod (Polar RP column)=2.04 min.

General Procedure for Preparation of a Nucleoside Prodrug Type PD-B:

Non-limiting examples of 3′-O-acylated mono-phosphoramidate prodrugscomprising the instant invention may be prepared according to generalScheme 5.

wherein R^(z) is (C₁-C₈)alkyl.

The general procedure comprises the reaction of Compound PD-A (R⁴═OH)with a carboxylic acid or an activated carboxylate such as an acylchloride or an acid anhydride, which is generally known to those skilledin the art (Journal of Medicinal Chemistry, 2006, 49, 6614 and OrganicLetters, 2003, 6, 807). When R⁸═NH₂, protection of the amino group maybe necessary. Briefly, to a solution of Compound PD-A in acetonitrile (2mL) is added N,N-dimethylformamide dimethyl acetal (˜1.1 eq.) andstirred at room temperature for 1 h. After the protection of 6-aminogroup is complete, the mixture is then concentrated to dryness. To theresidue are added a dehydrating agent such as DCC (˜4 eq.), acetonitrileand a carboxylic acid (˜2 eq.). The mixture is stirred at roomtemperature for 24-48 h. Water (0.2 mL) and trifluoroacetic acid (0.1mL) are added at 0° C. and stirred at room temperature for 64 h. Sodiumbicarbonate was added at 0° C. The mixture is stirred at roomtemperature for 0.5 h and filtered. The filtrate is concentrated and theresidue was purified by silica gel column chromatography to affordCompound PD-B. If an acyl chloride or an acid anhydride is used, asuitable base, such as triethylamine, is added instead of a dehydratingagent.

Compound 35

To a solution of Compound (S)-30 (34 mg, 0.062 mmol) in THF (0.8 mL)under an atmosphere of argon at room temperature was addedN,N-dimethylformamide-dimethylacetal (8.2 μL, 0.062 mmol). After 8 h, anadditional N,N-dimethylformamide-dimethylacetal (10 μL) was added andstirred for 16 h. The reaction mixture was concentrated. The reactionwas taken up in DCM and concentrated. This process was repeated twice.The resulting residue was taken up in THF (0.8 mL) and cooled to 0° C.under an atmosphere of argon. To the solution was added triethylamine(11 μL, 0.075 mmol) and DMAP (0.4 mg, 0.003 mmol). After 5 minutes,isobutyryl chloride (7.4 μL, 0.07 mmol) was added. After 30 minutes, thereaction was allowed to warm to room temperature and was stirred for 3hours. The mixture was cooled to 0° C., quenched with a 5% TFA solutionin water, and then allowed to stir at room temperature for 4 hours. Theresulting mixture was neutralized with solid sodium bicarbonate, dilutedwith water, and extracted with ethyl acetate (3×). The combined organiclayers were dried with sodium sulfate, filtered and concentrated. Theresidue was purified by RP HPLC (acetonitrile/water), affording Compound(S)-35 (32 mg, 83%). ¹H NMR (400 MHz, CDCl₃): δ 7.96 (br s, 1H), 7.76(d, 1H), 7.13-7.32 (m, 5H), 6.29 (br s, 1H) 5.94 (s, 1H), 5.87 (d, 1H),5.00 (m, 2H), 4.48-4.58 (m, 2H), 4.29 (m, 1H), 3.88-4.05 (m, 2H), 2.67(m, 1H), 1.39 (d, 3H), 1.22 (12H), 1.02 (s, 3H). ³¹P NMR (161 MHz,CDCl₃): δ 3.20 (s). LC/MS=622 (M+H⁺).

General Procedure for Preparation of a Nucleoside Prodrug Type PD-C:

Non-limiting examples of mono-phosphoramidate prodrugs comprising theinstant invention may be prepared according to general Scheme 6.

Scheme 6 illustrates chemical processes that may be useful forpreparation of Compound PD-C. Accordingly, Compound PD-A is converted toCompound PD-C in the presence of a base when Ar is substituted with anelectron-withdrawing p-nitro or p-chloro group (European Journal ofMedicinal Chemistry, 2009, 44, 3769). Alternatively, a Nucleoside isconverted to a cyclic phosphate Compound 71 according to Bioorganic andMedicinal Chemistry Letters, 2007, 17, 2452, which is then coupled withan amino acid ester salt to form Compound PD-C.

Compound 36

A solution of Compound 36a in DMSO is treated at room temperature withpotassium t-butoxide (˜1 eq.) and the resulting mixture is stirred forabout 10 min. to about 2 h. The mixture is then cooled to 0° C. andneutralized with 1N HCl to ˜pH 6. The mixture is purified by HPLC toafford Compound 36. The intermediate Compound 36a is obtained by thegeneral method for preparation of prodrug type Compound PD-A, startingwith Compound 100a (ArO=4-chlorophenol), Compound 100b (2′-ethylbutylester of alanine hydrochloride) and Compound 2.

Compound 37

Compound 2 is dissolved in PO(OMe)₃ (0.1-0.5 M solution) and cooled to0° C. under argon. To this stirring solution is added POCl₃(1.0-5.0 eq.)dropwise, and the reaction mixture is allowed to warm to roomtemperature for about 2-16 h. The resulting solution is added dropwiseto a rapidly stirring solution of acetonitrile and 0.05-0.5 M aqueousKOH. When addition is complete, the solvents are removed under reducedpressure. The resulting residue is dissolved in water and purified byHPLC to give Compound 71-2.

A solution of Compound 71-2 in DCM and PO(OMe)₃ is prepared and cooledto 0° C. To this solution is added oxalyl chloride (1.0-5.0 eq.)followed by a catalytic amount of DMF. The mixture is allowed to stirfor about 10 min. to about 1 h. When activation is complete, a largevolume of 2-propanol is added to the reaction mixture and allowed tostir and warm to room temperature. The solvents are removed underreduced pressure, and the resulting crude material is purified bypreparative HPLC to give Compound 37.

Compound 38

Compound 38 is prepared from Compound 71-2 in a matter similar to thatof Compound 37 substituting 2-aminopropane for 2-propanol.

Compound 39

A mixture of about 1.25 mmol of Compound 1 and about 1.9 mmol oftriethylammonium 2-(2,2-dimethyl-3-(trityloxy)propanoylthio)ethylphosphinate (WO2008082601) is dissolved in anhydrous pyridine (about 19mL). Pivaloyl chloride (about 2.5 mmol) is added dropwise at about −30to about 0° C. and the solution is stirred at for about 30 min to about24 hours. The reaction is diluted with methylene chloride and isneutralized with aqueous ammonium chloride (about 0.5 M). Thedichloromethane phase is evaporated and the residue is dried and ispurified by chromatography to give Compound 39.

Compound 40

To a solution of about 0.49 mmol of Compound 39 in anhydrous carbontetrachloride (about 5 mL) is added dropwise benzylamine (about 2.45mmol). The reaction mixture is stirred for about one to about 24 hours.The solvent is evaporated and the residue is purified by chromatographyto give Compound 40.

Compound 41

A solution of about 2 mmol of Compound 40 in dichloromethane (about 10mL) is treated with an aqueous solution of trifluoroacetic acid (90%,about 10 mL). The reaction mixture is stirred at about 25 to about 60°C. for about one to about 24 hours. The reaction mixture is diluted withethanol, the volatiles are evaporated and the residue is purified bychromatography to give Compound 41.

Compound 42

About 90 mM Compound 1 in THF is cooled to about −78° C. and about 2.2to about 5 equivalents of t-butylmagneisum chloride (about 1 M in THF)is added. The mixture is warmed to about 0° C. for about 30 min and isagain cooled to about −78° C. A solution of2-{[chloro(1-phenoxy)phosphoryl]amino}ethyl isobutyrate (WO2008085508)(1 M in THF, about 2 equivalents) is added dropwise. The cooling isremoved and the reaction is stirred for about one to about 24 hours. Thereaction is quenched with water and the mixture is extracted with ethylacetate. The extracts are dried and evaporated and the residue purifiedby chromatography to give Compound 42.

Antiviral Activity

Another aspect of the invention relates to methods of inhibiting viralinfections, comprising the step of treating a sample or subjectsuspected of needing such inhibition with a composition of theinvention.

Within the context of the invention samples suspected of containing avirus include natural or man-made materials such as living organisms;tissue or cell cultures; biological samples such as biological materialsamples (blood, serum, urine, cerebrospinal fluid, tears, sputum,saliva, tissue samples, and the like); laboratory samples; food, water,or air samples; bioproduct samples such as extracts of cells,particularly recombinant cells synthesizing a desired glycoprotein; andthe like. Typically the sample will be suspected of containing anorganism which induces a viral infection, frequently a pathogenicorganism such as a tumor virus. Samples can be contained in any mediumincluding water and organic solvent\water mixtures. Samples includeliving organisms such as humans, and man made materials such as cellcultures.

If desired, the anti-virus activity of a compound of the invention afterapplication of the composition can be observed by any method includingdirect and indirect methods of detecting such activity. Quantitative,qualitative, and semiquantitative methods of determining such activityare all contemplated. Typically one of the screening methods describedabove are applied, however, any other method such as observation of thephysiological properties of a living organism are also applicable.

The antiviral activity of a compound of the invention can be measuredusing standard screening protocols that are known. For example, theantiviral activity of a compound can be measured using the followinggeneral protocols.

Cell-Based Flavivirus Immunodetection Assay

BHK21 or A549 cells are trypsinized, counted and diluted to 2×10⁵cells/mL in Hams F-12 media (A549 cells) or RPMI-1640 media (BHK21cells) supplemented with 2% fetal bovine serum (FBS) and 1%penicillin/streptomycin. 2×10⁴ cells are dispensed in a clear 96-welltissue culture plates per well and placed at 37° C., 5% CO₂ overnight.On the next day, the cells are infected with viruses at multiplicity ofinfection (MOI) of 0.3 in the presence of varied concentrations of testcompounds for 1 hour at 37° C. and 5% CO₂ for another 48 hours. Thecells are washed once with PBS and fixed with cold methanol for 10 min.After washing twice with PBS, the fixed cells are blocked with PBScontaining 1% FBS and 0.05% Tween-20 for 1 hour at room temperature. Theprimary antibody solution (4G2) is then added at a concentration of 1:20to 1:100 in PBS containing 1% FBS and 0.05% Tween-20 for 3 hours. Thecells are then washed three times with PBS followed by one hourincubation with horseradish peroxidase(HRP)-conjugated anti-mouse IgG(Sigma, 1:2000 dilution). After washing three times with PBS, 50microliters of 3,3′,5,5′-tetramethylbenzidine (TMB) substrate solution(Sigma) is added to each well for two minutes. The reaction is stoppedby addition of 0.5 M sulfuric acid. The plates are read at 450 nmabsorbance for viral load quantification. After measurement, the cellsare washed three times with PBS followed by incubation with propidiumiodide for 5 min. The plate is read in a Tecan Safire™ reader(excitation 537 nm, emission 617 nm) for cell number quantification.Dose response curves are plotted from the mean absorbance versus the logof the concentration of test compounds. The EC₅₀ is calculated bynon-linear regression analysis. A positive control such asN-nonyl-deoxynojirimycin may be used.

Cell-Based Flavivirus Cytopathic Effect Assay

For testing against West Nile virus or Japanese encephalitis virus,BHK21 cells are trypsinized and diluted to a concentration of 4×10⁵cells/mL in RPMI-1640 media supplemented with 2% FBS and 1%penicillin/streptomycin. For testing against dengue virus, Huh7 cellsare trypsinized and diluted to a concentration of 4×10⁵ cells/mL in DMEMmedia supplemented with 5% FBS and 1% penicillin/streptomycin. A 50microliter of cell suspension (2×10⁴ cells) is dispensed per well in a96-well optical bottom PIT polymer-based plates (Nunc). Cells are grownovernight in culture medium at 37° C., 5% CO₂, and then infected withWest Nile virus (e.g., B956 strain) or Japanese encephalitis virus(e.g., Nakayama strain) at MOI=0.3, or with dengue virus (e.g., DEN-2NGC strain) at MOI=1, in the presence of different concentrations oftest compounds. The plates containing the virus and the compounds arefurther incubated at 37° C., 5% CO₂ for 72 hours. At the end ofincubation, 100 microliters of CellTiter-Glo™ reagent is added into eachwell. Contents are mixed for 2 minutes on an orbital shaker to inducecell lysis. The plates are incubated at room temperature for 10 minutesto stabilize luminescent signal. Luminescence reading is recorded usinga plate reader. A positive control such as N-nonyl-deoxynojirimycin maybe used.

Antiviral Activity in a Mouse Model of Dengue Infection

Compounds are tested in vivo in a mouse model of dengue virus infection(Schul et al. J. Infectious Dis. 2007; 195:665-74). Six to ten week oldAG129 mice (B&K Universal Ltd, HII, UK) are housed in individuallyventilated cages. Mice are injected intraperitoneally with 0.4 mL TSV01dengue virus 2 suspension. Blood samples are taken by retro orbitalpuncture under isoflurane anesthesia. Blood samples are collected intubes containing sodium citrate to a final concentration of 0.4%, andimmediately centrifuged for 3 minutes at 6000 g to obtain plasma. Plasma(20 microliters) is diluted in 780 microliters RPMI-1640 medium and snapfrozen in liquid nitrogen for plaque assay analysis. The remainingplasma is reserved for cytokine and NS1 protein level determination.Mice develop dengue viremia rising over several days, peaking on day 3post-infection.

For testing of antiviral activity, a compound of the invention isdissolved in vehicle fluid, e.g., 10% ethanol, 30% PEG 300 and 60% D5W(5% dextrose in water; or 6N HCl (1.5 eq):1N NaOH (pH adjusted to 3.5):100 mM citrate buffer pH 3.5 (0.9% v/v:2.5% v/v: 96.6% v/v). Thirty six6-10 week old AG129 mice are divided into six groups of six mice each.All mice are infected with dengue virus as described above (day 0).Group 1 is dosed by oral gavage of 200 mL/mouse with 0.2 mg/kg of acompound of the invention twice a day (once early in the morning andonce late in the afternoon) for three consecutive days starting on day 0(first dose just before dengue infection). Groups 2, 3 and 4 are dosedthe same way with 1 mg/kg, 5 mg/kg and 25 mg/kg of the compound,respectively. A positive control may be used, such as(2R,3R,4R,5R)-2-(2-amino-6-hydroxy-purin-9-yl)-5-hydroxymethyl-3-methyl-tetrahydro-furan-3,4-diol,dosed by oral gavage of 200 microliters/mouse the same way as theprevious groups. A further group is treated with only vehicle fluid.

On day 3 post-infection approximately 100 microliter blood samples(anti-coagulated with sodium citrate) are taken from the mice byretro-orbital puncture under isoflurane anesthesia. Plasma is obtainedfrom each blood sample by centrifugation and snap frozen in liquidnitrogen for plague assay analysis. The collected plasma samples areanalyzed by plague assay as described in Schul et al. Cytokines are alsoanalyzed as described by Schul. NS1 protein levels are analyzed using aPlatelia™ kit (BioRad Laboratories). An anti-viral effect is indicatedby a reduction in cytokine levels and/or NS1 protein levels.

Typically, reductions in viremia of about 5-100 fold, more typically10-60 fold, most typically 20-30 fold, are obtained with 5-50 mg/kg biddosages of the compounds of the invention.

HCV IC₅₀ Determination

Assay Protocol: Either wild type or S282T (Migliaccio, et al., J. Biol.Chem. 2003, 49164-49170; Klumpp, et al., J. Biol. Chem. 2006, 3793-3799)mutant polymerase enzyme was used in this assay. NS5b polymerase assay(40 μL) was assembled by adding 28 μL polymerase mixture (finalconcentration: 50 mM Tris-HCl at pH 7.5, 10 mM KCl, 5 mM MgCl₂, 1 mMDTT, 10 mM EDTA, 4 ng/μL of RNA template, and 75 nM HCV Δ21 NS5bpolymerase) to assay plates followed by 4 μL of compound dilution. Thepolymerase and compound were pre-incubated at 35° C. for 10 minutebefore the addition of 8 μL of nucleotide substrate mixture(33P-γ-labeled competing nucleotide at K_(M) and 0.5 mM of the remainingthree nucleotides). The assay plates were covered and incubated at 35°C. for 90 min. Reactions were then filtered through 96-well DEAE-81filter plates via vacuum. The filter plates were then washed undervacuum with multiple volumes of 0.125 M NaHPO₄, water, and ethanol toremove unincorporated label. Plates were then counted on TopCount toassess the level of product synthesis over background controls. The IC₅₀value is determined using Prism fitting program.

Preferably, compounds described herein inhibited NS5b polymerase withIC₅₀'s below 1000 μM, more preferably below 100 μM, and most preferablybelow 10 μM. Data for representative compounds are found in the Tablebelow.

Com- pound IC₅₀, # Structure μM 27

27 28

18

HCV EC₅₀ Determination

Replicon cells were seeded in 96-well plates at a density of 8×10³ cellsper well in 100 μL of culture medium, excluding Geneticin. Compound wasserially diluted in 100% DMSO and then added to the cells at a 1:200dilution, achieving a final concentration of 0.5% DMSO and a totalvolume of 200 μL. Plates were incubated at 37° C. for 3 days, afterwhich culture medium was removed and cells were lysed in lysis bufferprovided by Promega's luciferase assay system. Following themanufacturer's instruction, 100 μL of luciferase substrate was added tothe lysed cells and luciferase activity was measured in a TopCountluminometer. Preferably, compounds described herein have EC50's below1000 μM, more preferably below 100 μM, and most preferably below 10 μM.

Data for representative compounds are shown in the table below.

Com- pound EC₅₀, # Structure μM 29

8.2 30

2.6Mitochondrial Biogenesis Assay after 5-Day Treatment in PC-3 Cells

Three-fold serial dilutions of compounds were prepared in duplicate in96-well plates starting at a concentration close to the CC₅₀ value ofthe compound after 5-day treatment. For compounds with CC₅₀≧100 μM, thestarting concentration was 100 μM. PC-3 cells were plated at a densityof 2.5×10³ cells per well in a final assay volume of 100 μL per wellwith a constant amount of DMSO equal to 0.5%. After 5-day incubation,the cells were analyzed with the MitoSciences MitoBiogenesis™ In-CellELISA Kit (catalog #MS642), which uses quantitative immunocytochemistryto measure protein levels of Complexes II and IV in cultured cells.Cells were fixed in a 96-well plate and target proteins were detectedwith highly-specific, well-characterized monoclonal antibodies. Theprotein levels were quantified with IRDyee-labeled Secondary Antibodies.IR imaging and quantitation was performed using a LI-COR® Odysseyinstrument. All ratios were expressed as a percentage of the 0.5% DMSOcontrol. In cases where cell viability was severely affected, the datafor mitochondrial biogenesis was not included for analysis due tosignificant errors associated with low signals. Chloramphenicol was usedas the positive control for the assay.

The cytotoxicity of a compound of the invention can be determined usingthe following general protocol.

Cytotoxicity Cell Culture Assay (Determination of CC50)

The assay is based on the evaluation of cytotoxic effect of testedcompounds using a metabolic substrate.

Assay protocol for determination of CC₅₀:

-   1. Maintain MT-2 cells in RPMI-1640 medium supplemented with 5%    fetal bovine serum and antibiotics.-   2. Distribute the cells into a 96-well plate (20,000 cell in 100 μL    media per well) and add various concentrations of the tested    compound in triplicate (100 μL/well). Include untreated control.-   3. Incubate the cells for 5 days at 37° C.-   4. Prepare XTT solution (6 ml per assay plate) in dark at a    concentration of 2 mg/ml in a phosphate-buffered saline pH 7.4. Heat    the solution in a water-bath at 55° C. for 5 min. Add 50 μl of    N-methylphenazonium methasulfate (5 μg/mL) per 6 ml of XTT solution.-   5. Remove 100 μl media from each well on the assay plate and add 100    μl of the XTT substrate solution per well. Incubate at 37° C. for 45    to 60 min in a CO₂ incubator.-   6. Add 20 μl of 2% Triton X-100 per well to stop the metabolic    conversion of XTT.-   7. Read the absorbance at 450 nm with subtracting off the background    at 650 nm.-   8. Plot the percentage absorbance relative to untreated control and    estimate the CC₅₀ value as drug concentration resulting in a 50%    inhibition of the cell growth. Consider the absorbance being    directly proportional to the cell growth.

It has been observed that nucleoside analogs with R⁶ as currentlyclaimed can have enhanced cellular selectivity over their counterpartswith R⁶═H. As shown in the table below, structurally closely relatedcompounds Compound A (R⁶═H) and Compound 30 (R⁶═CN) had the same levelof antiviral activity, where Compound A displayed EC₅₀ of 2.5 μM andCompound 30 did EC₅₀ of 2.6 μM. However, mitochondrial toxicity of thesetwo compounds was surprisingly different from each other. Compound Ashowed 50% inhibition of mitochondrial protein levels at 43 μM, whileCompound 30 showed no inhibitory effect even at 100 μM, which was amaximum concentration tested in the Mitochondrial Biogenesis assay.

HCV EC50 Compound# Structure (uM) CC50 (μM) Chloramphenicol — —   2.5 A

2.5 43 30

2.6 Not toxic effect up to 100 μM

Anti-Influenza Assays

MDCK cells (Friedrich-Loeffler Institute, Riems, Germany) are grown inEagle minimum essential medium (EMEM) supplemented with 10% fetal bovineserum, 100 U/mL penicillin, and 100 U/mL streptomycin. Medium applied inplaque reduction assays is formulated with about 2 μg/mL trypsin andabout 1.2 mM bicarbonate and does not contain serum.

A/Horneburg/IDT7489/08 and Brest/IDT490/08 are isolated in embryonatedhens eggs and from nasal swabs obtained from pigs with clinicalsymptoms.

Stocks of H1N1 influenza virus A/PR/8/34 (Institute of Virology,Philipps University, Marburg), the oseltamivir-resistant human H1N1isolate N342109 (Robert Koch Institute, Berlin, Germany) and the porcineH1N1 isolates A/Belzig/2/01, A/Potsdam/15/81 (Dr. Schrader,Bundesinstitut for Risikoforschung, Berlin, Germany),A/Horneburg/IDT7489/08, and Brest/IDT490/08 are propagated in MDCKcells, aliquoted, and stored at −80° C. until use.

Immediately before use, compound stocks are prepared in water and storedat 4° C. Stock solutions of compounds are prepared in DMSO.

Cytotoxicity as well as antiviral activity of test compounds isdetermined on 3-day-old MDCK cell monolayers as described previously bySchmidtke (Antivir. Res. 2002, 55, 117-127). Briefly, to determine theCC₅₀, confluent cell monolayers grown in 96-well plates are incubatedwith serial 2-fold dilutions (each in triplicate) of compound, a testcompound or standard such as oseltamivir, for 72 h (37° C., 5% CO₂).Then the cells are fixed and stained with a crystal violet formalinsolution. After dye extraction, the optical density of individual wellsare quantified spectrophotometrically at 550/630 nm with a microplatereader. Cell viability of individual compound-treated wells areevaluated as the percentage of the mean value of optical densityresulting from six mock-treated cell controls which was set 100%. TheCC₅₀ is defined as the compound concentration reducing the viability ofuntreated cell cultures by 50%. It is calculated from the meandose-response curve of two independent assays.

A plaque reduction assay is used for antiviral testing with influenzavirus A/Puerto Rico/8/34 on MDCK cell. Cell monolayers are inoculatedwith approximately 70 plaque forming units (pfu) of the virus and areoverlaid with 0.4% agar supplemented with serial 2-fold compoundconcentrations; each tested in duplicate. One uninfected, untreated cellcontrol as well as three infected untreated virus controls are includedin all assays. After 48 h of incubation at 37° C., plates are fixed andstained with a crystal violet formalin solution, the number ofvirus-induced plaques are counted, and the compound-induced plaquereduction is calculated. The concentration required to reduce the plaquenumber by 50% is calculated from the mean dose-response curves of atleast 2 independent assays.

Anti-Enterovirus Assays

Clinical virus isolates are passaged once in the cell line used fortheir original isolation to establish working virus stocks and are thenstored as aliquots in glass ampoules at −80° C. Enteroviruses (EVs) arepropagated in human embryonal rhabdomyosarcoma (RD) cells grown inminimal essential medium (MEM) supplemented with 10% heat-inactivatedfetal bovine serum (FBS). CVA9 and CVB isolates are passaged inLLC-MK_(2D) cells grown in MEM plus 5% FBS. Viruses are assayed for drugsensitivity in the cell line used for their original isolation with theexception of the CVA9 isolates, which are assayed in HeLa cells.

Virus Cytopathic Effect Assay

The sensitivities of enteroviruses to compounds of Formula I may bedetermined in a cell culture assay that measures the protection by thedrug of an infected cell monolayer from the cytopathic effects of theviruses. Examples of prototypical strains of the 15 most commonlyisolated enteroviruses (Strikas, et al., J. Infect. Dis. 1986, 153,346-351) are shown in Table II Ninety-six-well tissue culture plates(Costar 3598) are seeded at a density of 2.8×10⁴ cells/well for HeLacells (in MEM plus 5% FBS), 3.6×10⁴ cells/well for LLC-MK_(2D) cells (inMEM plus 5% FBS), or 6×10⁴ cells/well for RD cells (in MEM plus 10%FBS). The cells are incubated for 24 h at 37° C. in a humidified, 5% CO₂atmosphere prior to their use in the assay.

To determine the virus inoculum in the assay, serial 0.5 log₁₀ dilutionsof individual viruses are plated in octuplicate onto their respectivecell lines in medium 199 (M199) plus 5% FBS supplemented with 30 mMMgCl₂ and 15 μg of DEAE dextran per ml (complete M199 medium). Theplates are incubated for 3 days and are then fixed with 5%glutaraldehyde and stained with 0.1% crystal violet. After rinsing anddrying, the optical density of the wells at a wavelength of 570 nm(OD₅₇₀) are read on a Bio-Tek 300 plate reader. The highest dilution ofvirus that produces an OD₅₇₀ reading of ≦15% of the cell culture controlvalue is used for drug sensitivity testing.

To test for drug sensitivity, cells in 96-well plates are infected withthe appropriate virus dilution at 37° C. in 150 μl of complete M199medium. During the 1-h virus attachment period, compounds of Formula Iare solubilized in dimethyl sulfoxide (DMSO) to 400 times the highestconcentration to be tested in the assay and are then serially dilutedtwofold in DMSO in U-bottom, 96-well polypropylene plates (Costar 3790)to yield 10 compound dilutions. Two microliters of the DMSO compounddilutions are then diluted into 198 μl of complete M199 medium to effecta 100-fold dilution of compound. After virus attachment, 50 μl of thisdrug dilution is added to the 150 μl virus inoculum, resulting in afinal 400-fold dilution of compound in 0.25% DMSO. Each compoundconcentration is run in quadruplicate. Uninfected cells and cells thatreceive virus in the absence of compound are included on each plate. Theplates are then incubated for 3 days at 37° C. in a humidified, 2.5% CO₂atmosphere prior to fixation and staining. The 50% inhibitoryconcentration (IC₅₀) is defined as the concentration of compound thatprotects 50% of the cell monolayer from virus-induced cytopathic effect.

TABLE 4 Commonly isolated enteroviruses. EV3 Morrisey EV4 Pesacek EV5Noyce EV6 D'Amori EV7 Wallace EV9 Hill EV11 (Gregory) EV24 (DeCamp) EV30(Bastianni) CVA9 Bozek CVB1 Conn-5 CVB2 Ohio-1 CVB3 Nancy CVB3 M CVB4JVB CVB5 Faulkner

Respiratory Syncytial Virus (RSV) Antiviral Activity and CytotoxicityAssays Anti-RSV Activity

Antiviral activity against RSV is determined using an in vitrocytoprotection assay in Hep2 cells. In this assay, compounds inhibitingthe virus replication exhibit cytoprotective effect against thevirus-induced cell killing that can be quantified using a cell viabilityreagent. The method used is similar to methods previously described inpublished literature (Chapman et al., Antimicrob Agents Chemother. 2007,51(9):3346-53.)

Hep2 cells are obtained from ATCC (Manassas, VI) and maintained in MEMmedia supplemented with 10% fetal bovine serum andpenicillin/streptomycin. Cells are passaged twice a week and kept atsubconfluent stage. Commercial stock of RSV strain A2 (AdvancedBiotechnologies, Columbia, Md.) is titered before compound testing todetermine the appropriate dilution of the virus stock that generatesdesirable cytopathic effect in Hep2 cells.

For antiviral tests, Hep2 cells are seeded into 96-well plates 24 hoursbefore the assay at a density of 3,000 cells/well. On a separate 96wellplate, compounds to be tested are serially diluted in cell culturemedia. Eight concentrations in 3-fold serial dilution increments areprepared for each tested compound and 100 μL/well of each dilution istransferred in duplicate onto plates with seeded Hep2 cells.Subsequently, appropriate dilution of virus stock previously determinedby titration is prepared in cell culture media and 100 μL/well is addedto test plates containing cells and serially diluted compounds. Eachplate includes three wells of infected untreated cells and three wellsof uninfected cells that served as 0% and 100% virus inhibition control,respectively. Following the infection with RSV, testing plates areincubated for 4 days in a tissue culture incubator. After theincubation, RSV-induced cytopathic effect is determined using a CellTiterGlo reagent (Promega, Madison, Wis.) followed by a luminescenceread-out. The percentage inhibition is calculated for each testedconcentration relative to the 0% and 100% inhibition controls and theEC50 value for each compound is determined by non-linear regression as aconcentration inhibiting the RSV-induced cytopathic effect by 50%.Ribavirin (purchased from Sigma, St. Louis, Mo.) is used as a positivecontrol for antiviral activity.

Compounds were also tested for antiviral activity against RSV in Hep2cells using a 384 well format. Compounds were diluted in DMSO using a10-step serial dilution in 3-fold increments via automation in 4adjacent replicates each. Eight compounds were tested per dilutionplate. 0.4 uL of diluted compounds were then stamped via Biomek into384-well plates (Nunc 142761 or 164730 w/lid 264616) containing 20 μL ofmedia (Mediatech Inc. MEM supplemented with Glutamine, 10% FBS andPen/Strep). DMSO and a suitable positive control compound, such as 80 μMGS-329467 or 10 μM 427346 was used for the 100% and 0% cell killingcontrols, respectively.

Hep2 cells (1.0×105 cells/mil) were prepared as above in batch to atleast 40 mls excess of the number of sample plates (8 mls cell mix perplate) and infected with vendor supplied (ABI) RSV strain A2 to arriveat an MOI of 1:1000 (virus:cell #) or 1:3000 (vol virus: cell vol).Immediately after addition of virus, the RSV infected Hep2 cellsuspension was added to each stamped 384-well plate at 20 μl per wellusing a uFlow dispenser, giving a final volume of 40 μL/well, each with2000 infected cells. The plates were then incubated for 5 days at 37° C.and 5% CO₂. Following incubation, the plates were equilibrated to roomtemperature in a biosafety cabinet hood for 1.5 hrs and 40 μL ofCell-Titer Glo viability reagent (Promega) was added to each well viauFlow. Following a10-20 minute incubation, the plates were read using anEnVision or Victor Luminescence plate reader (Perkin-Elmer). The datawas then uploaded and analyzed on the Bioinformatics portal under theRSV Cell Infectivity and 8-plate EC50-Hep2-384 or 8-plateEC50-Hep2-Envision protocols.

Representative activity for the compounds of the invention againstRSV-induced cytopathic effects using 384 well method are shown in theTable below.

Com- pound EC₅₀ # Structure (μM) 3

10.865 4

11.302 10

200 11

200 12

200 13

200 15

200 30

200 35

200

Cytotoxicity

Cytotoxicity of tested compounds is determined in uninfected Hep2 cellsin parallel with the antiviral activity using the cell viability reagentin a similar fashion as described before for other cell types (Cihlar etal., Antimicrob Agents Chemother. 2008, 52(2):655-65.). The sameprotocol as for the determination of antiviral activity is used for themeasurement of compound cytotoxicity except that the cells are notinfected with RSV. Instead, fresh cell culture media (100 μL/well)without the virus is added to tested plates with cells and predilutedcompounds. Cells are then incubated for 4 days followed by a cellviability test using CellTiter Glo reagent and a luminescence read-out.Untreated cell and cells treated with 50 ug/mL puromycin (Sigma, St.Louis, Mo.) are used as 100% and 0% cell viability control,respectively. The percent of cell viability is calculated for eachtested compound concentration relative to the 0% and 100% controls andthe CC₅₀ value is determined by non-linear regression as a compoundconcentration reducing the cell viability by 50%.

All publications, patents, and patent documents cited herein above areincorporated by reference herein, as though individually incorporated byreference. The invention has been described with reference to variousspecific and preferred embodiments and techniques. However, one skilledin the art will understand that many variations and modifications may bemade while remaining within the spirit and scope of the invention.

1. A compound of Formula I:

or a pharmaceutically acceptable salt thereof; wherein: Base is anaturally occurring or modified pyrimidine base; R¹ is H, CN, OR^(a),(C₁-C₄)alkyl, (C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl,(C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl, (C₂-C₄)substituted alkynylor S(O)_(n)R^(a); R² is H, OR^(a), N(R^(a))₂, N₃, CN, NO₂,S(O)_(n)R^(a), (C₁-C₄)alkyl, (C₄-C₆)cycloalkylalkyl, (C₁-C₄)substitutedalkyl, (C₂-C₄)alkenyl, (C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl, or(C₂-C₄)substituted alkynyl; or R¹ and R² taken together with the carbonto which they are attached form a 3-to 6-membered cycloalkyl ringwherein 1 to 3 carbon atoms of said cycloalkyl ring is optionallyreplaced by O or S(O)_(n); R³, R⁴, and R⁵ are each independently H,OR^(a), N(R^(a))₂, N₃, CN, NO₂, S(O)_(n)R^(a), halogen, (C₁-C₄)alkyl,(C₄-C₈)cycloalkylalkyl, (C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl,(C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl, or (C₂-C₄)substitutedalkynyl; or any two of R³, R⁴ or R⁵ on adjacent carbon atoms when takentogether are —O(CO)O— or when taken together with the ring carbon atomsto which they are attached to form a double bond; R⁶ is CN, ethenyl,2-haloethen-1-yl, or (C₂-C₈)alkyn-1-yl, each n is independently 0, 1, or2; each R^(a) is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, aryl(C₁-C₈)alkyl, (C₄-C₈)cycloalkylalkyl, —C(═O)R¹¹,—C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹, —S(O)₂R¹¹, —S(O)(OR¹¹),—S(O)₂(OR¹¹), or —SO₂NR¹¹R¹²; R⁷ is H, —C(═O)R¹¹, —C(═O)OR¹¹,—C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹, —S(O)₂R¹¹, —S(O)(OR¹¹),—S(O)₂(OR¹¹), —SO₂NR¹¹R¹², or the group of Formula Ia

wherein Y is O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂; W¹ and W²,when taken together, are —Y³(C(R^(y))₂)₃Y³—; or one of W¹ or W² togetherwith either R³ or R⁴ is —Y³— and the other of W¹ or W² is Formula Ib; orW¹ and W² are each, independently, a group of Formula Ib:

wherein: each Y¹ is independently O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR),or N—NR₂; each Y² is independently a bond, O, CR₂, NR, ⁺N(O)(R), N(OR),⁺N(O)(OR), N—NR₂, S, S—S, S(O), or S(O)₂; each Y³ is independently O, S,or NR; M2 is 0, 1, or 2; each R^(x) is a group of Formula Ic

wherein: each M1a, M1c, and M1d is independently 0 or 1; M1b is 0, 1, 2,3, 4, 5, 6, 7, 8, 9, 10, 11 or 12; each R^(y) is independently H, F, Cl,Br, I, —CN, —N₃, —NO₂, —OR, —C(R)₂—O—C(R)₃, —C(═Y¹)R, —C(═Y¹)R¹³,—C(═Y¹)OR, —C(═Y¹)N(R)₂, —N(R)₂, —⁺N(R)₃, —SR, —S(O)R, —S(O)₂R,—S(O)₂R¹³, —S(O)(OR), —S(O)₂(OR), —OC(═Y¹)R, —OC(═Y¹)OR,—OC(═Y¹)(N(R)₂), —SC(═Y¹)R, —SC(═Y¹)OR, —SC(═Y¹)(N(R)₂), —N(R)C(═Y¹)R,—N(R)C(═Y¹)OR, —N(R)C(═Y¹)N(R)₂, —SO₂NR₂, (C₁-C₈) alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, C₆-C₂₀ aryl, C₃-C₂₀ cycloalkyl, (C₂-C₂₀) heterocyclyl,arylalkyl, or heteroarylalkyl, wherein each (C₁-C₈) alkyl,(C₂-C₈)alkenyl, (C₂-C₈) alkynyl, (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl,(C₂-C₂₀) heterocyclyl, arylalkyl, or heteroarylalkyl is optionallysubstituted with 1-3 R²⁰ groups; or when taken together, two R^(y)groups on the same carbon atom form a cycloalkyl ring of 3 to 7 carbonatoms; each R is independently H, (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈)alkynyl, (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl, orarylalkyl; R⁸ is H, (C₁-C₄) alkyl, or (C₁-C₄) substituted alkyl; eachR¹¹ or R¹² is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, (C₄-C₈)cycloalkylalkyl, (C₃-C₂₀)cycloalkyl,(C₂-C₂₀)heterocyclyl, optionally substituted aryl, optionallysubstituted heteroaryl, —C(═O)(C₁-C₈)alkyl, —S(O)_(n)(C₁-C₈)alkyl oraryl(C₁-C₈)alkyl; or R¹¹ and R¹² taken together with a nitrogen to whichthey are both attached form a 3-to 7-membered heterocyclic ring whereinany one carbon atom of said heterocyclic ring can optionally be replacedwith —O—, —S— or —NR^(a)—; each R¹³ is independently a cycloalkyl orheterocycle optionally substituted with 1-3 R or R²⁰ groups; each R²⁰ isindependently, halogen, CN, N₃, N(R)₂, OR, —SR, —S(O)R, —S(O)₂R,—S(O)(OR), —S(O)₂(OR), —C(═Y¹)R, —C(═Y¹)OR, or C(═Y¹)N(R)₂; wherein eachalkyl, alkenyl, alkynyl, aryl or heteroaryl of each of R¹, R², R³, R⁴,R⁵, R⁸, R¹¹ or R¹² is, independently, optionally substituted with 1 to 3halo, hydroxy, CN, N₃, N(R^(a))₂ or OR^(a); and wherein 1 to 3 of thenon-terminal carbon atoms of each said (C₁-C₈)alkyl may be optionallyreplaced with —O—, —S— or —NR^(a)—; with the following provisos: a) whenR¹, R³, and R⁵ are hydrogen, R² and R⁴ are hydroxy, R⁶ is cyano and R⁷and R⁸ are hydrogen, then Base is not uracil or thymine; b) when R¹ andR⁴ are hydroxy, R², R³, and R⁵ are hydrogen, R⁶ is cyano and R⁷ and R⁸are hydrogen, then Base is not uracil or cytosine; c) when R¹, R², R³,and R⁵ are hydrogen, R⁴ is hydroxy, R⁶ is cyano and R⁷ and R⁸ arehydrogen, then Base is not uracil, cytosine, thymine or 5-iodo-uracil;d) when R¹, R³, and R⁵ are hydrogen, R² and R⁴ are hydroxy, R⁶ isethenyl and R⁷ and R⁸ are hydrogen, then Base is not uracil or cytosine;e) when R⁵ is other than H, then R⁸ is H; f) when R¹ is hydroxy, R², R³,R⁵, and R⁸ are hydrogen, R⁶ is cyano, R⁴ is hydrogen or benzoyl, and R⁷is hydrogen or benzoyl, then Base is not cytosine; g) when R¹ is acetylor hydroxy, R², R³, R⁵, R⁷, and R⁸ are hydrogen, R⁴ is hydroxy or—OC(O)phenyl, then Base is not 2-oxo-4-hydroxypyrimidinyl; h) when R¹ isacetoxy, R⁴ is benzoyloxy, R⁶ is cyano, R⁷ is benzoyl, and R², R³, R⁵,and R⁸ are hydrogen, then base is not uracil; and i) at least one of R¹,R², R³, R⁴ and R⁵ is not hydrogen.
 2. The compound according to claim 1represented by Formula II:

wherein each Y and Y¹ is O.
 3. The compound according to claim 1represented by Formula III:

wherein each Y and Y¹ is O.
 4. The compound according to claim 1represented by Formula IV:

wherein each Y and Y¹ is O.
 5. The compound according to claim 1represented by Formula V:

wherein each Y and Y¹ is O and X is halogen.
 6. The compound accordingto claim 5, wherein halogen is fluoro, chloro, or iodo.
 7. The compoundaccording to claim 1, wherein R¹ is H, CN, OR^(a), (C₁-C₄)alkyl,(C₂-C₄)alkenyl, or (C₂-C₄)alkynyl.
 8. The compound according to claim 7,wherein R¹ is hydrogen, methyl, or hydroxy.
 9. The compound according toclaim 1, wherein R² is H or OR^(a).
 10. The compound according to claim9, wherein R² is hydrogen, methoxy, or hydroxy.
 11. The compoundaccording to claim 1, wherein R¹ and R² taken together with the carbonto which they are attached form a 4-membered cycloalkyl ring wherein onecarbon atom of said cycloalkyl ring is optionally replaced by O.
 12. Thecompound according to claim 1, wherein R³, R⁴, and R⁵ are eachindependently H, OR^(a), N₃, CN, (C₁-C₄) alkyl, or (C₂-C₄) alkynyl. 13.The compound according to claim 12, wherein R³, R⁴, and R⁵ are eachindependently H, hydroxy, N₃, or —OC(O)-isopropyl.
 14. The compoundaccording to claim 1, wherein Base is uracil optionally substituted withhalogen.
 15. The compound according to claim 1, wherein Base is cytosineoptionally substituted with halogen.
 16. The compound according to claim1, wherein Base is a pyrimidine represented by Formula VI or VII:

or tautomer thereof, wherein: each X¹ or X² is independently C—R¹⁰ or Nprovided that at least one of X¹ or X² is C—R¹⁰; each R⁹ is H, halogen,NR¹¹R¹², N(R¹¹)OR¹¹, NR¹¹NR¹¹R¹², N₃, NO, NO₂, OR¹¹ or SR¹¹; and eachR¹⁰ is independently H, halogen, NR¹¹R¹², N(R¹¹)OR¹¹, NR¹¹NR¹¹R¹², N₃,NO, NO₂, CHO, CN, —CH(═NR¹¹), —CH═NHNR¹¹, —CH═N(OR¹¹), —CH(OR¹¹)₂,—C(═O)NR¹¹R¹², —C(═S)NR¹¹R¹², —C(═O)OR¹¹, R¹¹, OR¹¹ or SR¹¹; each R¹¹ orR¹² is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl, (C₂-C₈)alkynyl,(C₄-C₈)cycloalkylalkyl, (C₃-C₂₀)cycloalkyl, (C₂-C₂₀)heterocyclyl,optionally substituted aryl, optionally substituted heteroaryl,—C(═O)(C₁-C₈)alkyl, —S(O)_(n)(C₁-C₈)alkyl or aryl(C₁-C₈)alkyl; or R¹¹and R¹² taken together with a nitrogen to which they are both attachedform a 3-to 7-membered heterocyclic ring wherein any one carbon atom ofsaid heterocyclic ring can optionally be replaced with —S— or —NR^(a)—;and R¹⁴ is H, (C₁-C₈)alkyl, or (C₄-C₈)cycloalkylalkyl.
 17. The compoundaccording to claim 1, wherein R⁶ is CN, ethenyl, or ethynyl.
 18. Thecompound according to claim 1, wherein R⁷ is H or


19. The compound according to claim 1, wherein R⁷ is H or

wherein W¹ and W² are each, independently, a group of the Formula Ib.20. The compound according to claim 1, wherein R¹ is H, OH, CN,(C₁-C₄)alkyl, (C₂-C₄)alkenyl, or (C₂-C₄)alkynyl; R² is H, OH orO(C₁-C₄)alkyl; or R¹ and R² taken together with the carbon to which theyare attached form a 3- to 6-membered cycloalkyl ring wherein one carbonatom of said cycloalkyl ring is optionally replaced by O; R³ is H or(C₁-C₄)alkyl; R⁴ is H, OH, O(C₁-C₄)alkyl, or OC(O)—(C₁-C₄)alkyl; R⁵ isH, CN, N₃, (C₁-C₄)alkyl, (C₂-C₄)alkenyl, or (C₂-C₄)alkynyl; R⁶ is CN,ethenyl, 2-haloethen-1-yl, or (C₂-C₈)alkyn-1-yl; and R⁸ is H or(C₁-C₄)alkyl.
 21. The compound of claim 1, wherein: R¹ is H, OH, or(C₁-C₄)alkyl; R² is H, OH or O(C₁-C₄)alkyl; or R¹ and R² taken togetherwith the carbon to which they are attached form a 4-membered cycloalkylring wherein one carbon atom of said cycloalkyl ring is optionallyreplaced by O; R³ is H or (C₁-C₄)alkyl; R⁴ is H, OH, O(C₁-C₄)alkyl, or—OC(O)—(C₁-C₄)alkyl; R⁵ is H, N₃, or (C₁-C₄)alkyl; R⁶ is CN, ethenyl, orethynyl; and R⁸ is H or (C₁-C₄) alkyl.
 22. The compound according toclaim 1, wherein R⁷ is H or


23. The compound according to claim 1, wherein the group—R⁷—O—C(R⁸)—C(R⁵)—C(R³)(R⁴)— is of the following formula:


24. The compound according to claim 1, wherein at least one of R¹, R²,R³, and R⁴ are hydroxy.
 25. The compound according to claim 24, whereinat least two of R¹, R², R³, and R⁴ are hydroxy.
 26. A compound selectedfrom

or a pharmaceutically acceptable salt thereof.
 27. A pharmaceuticalcomposition comprising a therapeutically effective amount of a compoundof claim 1 and a pharmaceutically acceptable carrier.
 28. Apharmaceutical composition comprising a pharmaceutically acceptablecarrier and a compound of Formula I:

or a pharmaceutically acceptable salt thereof; wherein: Base is anaturally occurring or modified pyrimidine base; R¹ is H, CN, OR^(a),(C₁-C₄)alkyl, (C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl,(C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl, (C₂-C₄)substituted alkynylor S(O)_(n)R^(a); R² is H, OR^(a), N(R^(a))₂, N₃, CN, NO₂,S(O)_(n)R^(a), (C₁-C₄)alkyl, (C₄-C₆)cycloalkylalkyl, (C₁-C₄)substitutedalkyl, (C₂-C₄)alkenyl, (C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl, or(C₂-C₄)substituted alkynyl; or R¹ and R² taken together with the carbonto which they are attached form a 3-to 6-membered cycloalkyl ringwherein 1 to 3 carbon atoms of said cycloalkyl ring is optionallyreplaced by O or S(O)_(n); R³, R⁴, and R⁵ are each independently H,OR^(a), N(R^(a))₂, N₃, CN, NO₂, S(O)_(n)R^(a), halogen, (C₁-C₄)alkyl,(C₄-C₈)cycloalkylalkyl, (C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl,(C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl, or (C₂-C₄)substitutedalkynyl; or any two of R³, R⁴ or R⁵ on adjacent carbon atoms when takentogether are —O(CO)O— or when taken together with the ring carbon atomsto which they are attached to form a double bond; R⁶ is CN, ethenyl,2-haloethen-1-yl, or (C₂-C₈)alkyn-1-yl, each n is independently 0, 1, or2; each R^(a) is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, aryl(C₁-C₈)alkyl, (C₄-C₈)cycloalkylalkyl, —C(═O)R¹¹,—C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹, —S(O)₂R¹¹, —S(O)(OR¹¹),—S(O)₂(OR¹¹), or —SO₂NR¹¹R¹²; R⁷ is H, —C(═O)R¹¹, —C(═O)OR¹¹,—C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹, —S(O)₂R¹¹, —S(O)(OR¹¹),—S(O)₂(OR¹¹), —SO₂NR¹¹R¹², or the group of Formula Ia

wherein Y is O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂; W¹ and W²,when taken together, are —Y³(C(R^(y))₂)₃Y³—; or one of W′ or W² togetherwith either R³ or R⁴ is —Y³— and the other of W¹ or W² is Formula Ib; orW¹ and W² are each, independently, a group of Formula Ib:

wherein: each Y¹ is independently O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR),or N—NR₂; each Y² is independently a bond, O, CR₂, NR, ⁺N(O)(R), N(OR),⁺N(O)(OR), N—NR₂, S, S—S, S(O), or S(O)₂; each Y³ is independently O, S,or NR; M2 is 0, 1, or 2; each R^(x) is a group of Formula Ic

wherein: each M1a, M1c, and M1d is independently 0 or 1; M1b is 0, 1, 2,3, 4, 5, 6, 7, 8, 9, 10, 11 or 12; each R^(y) is independently H, F, Cl,Br, I, —CN, —N₃, —NO₂, —OR, —C(R)₂—O—C(R)₃, —C(═Y¹)R, —C(═Y¹)R¹³,—C(═Y¹)OR, —C(═Y¹)N(R)₂, —N(R)₂, —⁺N(R)₃, —SR, —S(O)R, —S(O)₂R,—S(O)₂R¹³, —S(O)(OR), —S(O)₂(OR), —OC(═Y¹)R, —OC(═Y¹)OR,—OC(═Y¹)(N(R)₂), —SC(═Y¹)R, —SC(═Y¹)OR, —SC(═Y¹)(N(R)₂), —N(R)C(═Y¹)R,—N(R)C(═Y¹)OR, —N(R)C(═Y¹)N(R)₂, —SO₂NR₂, (C₁-C₈) alkyl, (C₂-C₈)alkenyl,(C₂-C₈) alkynyl, (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀)heterocyclyl, arylalkyl, or heteroarylalkyl, wherein each (C₁-C₈) alkyl,(C₂-C₈)alkenyl, (C₂-C₈) alkynyl, (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl,(C₂-C₂₀) heterocyclyl, arylalkyl, or heteroarylalkyl is optionallysubstituted with 1-3 R²⁰ groups; or when taken together, two R^(y) onthe same carbon atom form a cycloalkyl ring of 3 to 7 carbon atoms; eachR is independently H, (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈) alkynyl,(C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl, or arylalkyl;R⁸ is H, (C₁-C₄) alkyl, or (C₁-C₄) substituted alkyl; each R¹¹ or R¹² isindependently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl, (C₂-C₈)alkynyl,(C₄-C₈)cycloalkylalkyl, (C₃-C₂₀)cycloalkyl, (C₂-C₂₀)heterocyclyl,optionally substituted aryl, optionally substituted heteroaryl,—C(═O)(C₁-C₈)alkyl, —S(O)_(n)(C₁-C₈)alkyl or aryl(C₁-C₈)alkyl; or R¹¹and R¹² taken together with a nitrogen to which they are both attachedform a 3-to 7-membered heterocyclic ring wherein any one carbon atom ofsaid heterocyclic ring can optionally be replaced with —O—, —S— or—NR^(a)—; each R¹³ is independently a cycloalkyl or heterocycleoptionally substituted with 1-3 R or R²⁰ groups; each R²⁰ isindependently, halogen, CN, N₃, N(R)₂, OR, —SR, —S(O)R, —S(O)₂R,—S(O)(OR), —S(O)₂(OR), —C(═Y¹)R, —C(═Y¹)OR, or C(═Y¹)N(R)₂; wherein eachalkyl, alkenyl, alkynyl, aryl or heteroaryl of each of R¹, R², R³, R⁴,R⁵, R⁸, R¹¹ or R¹² is, independently, optionally substituted with 1 to 3halo, hydroxy, CN, N₃, N(R^(a))₂ or OR^(a); and wherein 1 to 3 of thenon-terminal carbon atoms of each said (C₁-C₈)alkyl may be optionallyreplaced with —O—, —S— or —NR^(a)— with the proviso that at least one ofR¹, R², R³, R⁴ and R⁵ is not hydrogen.
 29. The pharmaceuticalcomposition of claim 28 further comprising at least one additionaltherapeutic agent selected from the group consisting of interferons,ribavirin analogs, NS3 protease inhibitors, NS5a inhibitors, NS5bpolymerase inhibitors, alpha-glucosidase 1 inhibitors, cyclophilininhibitors, hepatoprotectants, other nucleoside inhibitors of HCV,non-nucleoside inhibitors of HCV, and other drugs for treating HCV. 30.The pharmaceutical composition of claim 28 further comprising at leastone viral neuramidase inhibitor or viral M2 channel inhibitor.
 31. Thepharmaceutical composition of claim 30, wherein the viral neuramidaseinhibitor or viral M2 channel inhibitor is selected from the groupconsisting of oseltamivir, zanamivir, laninamivir, peramivir, amantadineand rimantadine.
 32. The pharmaceutical composition of claim 30 furthercomprising pleconaril, BTA-798, or both pleconaril and BTA-798.
 33. Amethod of inhibiting HCV polymerase comprising administering to a mammalin need thereof a therapeutically effective amount of a compound ofclaim
 1. 34. A method of inhibiting HCV polymerase comprisingadministering to a mammal in need thereof a therapeutically effectiveamount of a compound of Formula I:

or a pharmaceutically acceptable salt thereof; wherein: Base is anaturally occurring or modified pyrimidine base; R¹ is H, CN, OR^(a),(C₁-C₄)alkyl, (C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl,(C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl, (C₂-C₄)substituted alkynylor S(O)_(n)R^(a); R² is H, OR^(a), N(R^(a))₂, N₃, CN, NO₂,S(O)_(n)R^(a), (C₁-C₄)alkyl, (C₄-C₆)cycloalkylalkyl, (C₁-C₄)substitutedalkyl, (C₂-C₄)alkenyl, (C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl, or(C₂-C₄)substituted alkynyl; or R¹ and R² taken together with the carbonto which they are attached form a 3-to 6-membered cycloalkyl ringwherein 1 to 3 carbon atoms of said cycloalkyl ring is optionallyreplaced by O or S(O)_(n); R³, R⁴, and R⁵ are each independently H,OR^(a), N(R^(a))₂, N₃, CN, NO₂, S(O)_(n)R^(a), halogen, (C₁-C₄)alkyl,(C₄-C₈)cycloalkylalkyl, (C₁-C₄)substituted alkyl, (C₂-C₄)alkenyl,(C₂-C₄)substituted alkenyl, (C₂-C₄)alkynyl, or (C₂-C₄)substitutedalkynyl; or any two of R³, R⁴ or R⁵ on adjacent carbon atoms when takentogether are —O(CO)O— or when taken together with the ring carbon atomsto which they are attached to form a double bond; R⁶ is CN, ethenyl,2-haloethen-1-yl, or (C₂-C₈)alkyn-1-yl, each n is independently 0, 1, or2; each R^(a) is independently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl,(C₂-C₈)alkynyl, aryl(C₁-C₈)alkyl, (C₄-C₈)cycloalkylalkyl, —C(═O)R¹¹,—C(═O)OR¹¹, —C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹, —S(O)₂R¹¹, —S(O)(OR¹¹),—S(O)₂(OR¹¹), or —SO₂NR¹¹R¹²; R⁷ is H, —C(═O)R¹¹, —C(═O)OR¹¹,—C(═O)NR¹¹R¹², —C(═O)SR¹¹, —S(O)R¹¹, —S(O)₂R¹¹, —S(O)(OR¹¹),—S(O)₂(OR¹¹), —SO₂NR¹¹R¹², or the group of Formula Ia

wherein Y is O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR), or N—NR₂; W¹ and W²,when taken together, are —Y³(C(R^(y))₂)₃Y³—; or one of W¹ or W² togetherwith either R³ or R⁴ is —Y³— and the other of W¹ or W² is Formula Ib; orW¹ and W² are each, independently, a group of Formula Ib:

wherein: each Y¹ is independently O, S, NR, ⁺N(O)(R), N(OR), ⁺N(O)(OR),or N—NR₂; each Y² is independently a bond, O, CR₂, NR, ⁺N(O)(R), N(OR),⁺N(O)(OR), N—NR₂, S, S—S, S(O), or S(O)₂; each Y³ is independently O, S,or NR; M2 is 0, 1, or 2; each R^(x) is a group of Formula Ic

wherein: each M1a, M1c, and M1d is independently 0 or 1; M1b is 0, 1, 2,3, 4, 5, 6, 7, 8, 9, 10, 11 or 12; each R^(y) is independently H, F, Cl,Br, I, —CN, —N₃, —NO₂, —OR, —C(R)₂—O—C(R)₃, —C(═Y¹)R, —C(═Y¹)R¹³,—C(═Y¹)OR, —C(═Y¹)N(R)₂, —N(R)₂, —⁺N(R)₃, —SR, —S(O)R, —S(O)₂R,—S(O)₂R¹³, —S(O)(OR), —S(O)₂(OR), —OC(═Y¹)R, —OC(═Y¹)OR,—OC(═Y¹)(N(R)₂), —SC(═Y¹)R, —SC(═Y¹)OR, —SC(═Y¹)(N(R)₂), —N(R)C(═Y¹)R,—N(R)C(═Y¹)OR, —N(R)C(═Y¹)N(R)₂, —SO₂NR₂, (C₁-C₈) alkyl, (C₂-C₈)alkenyl,(C₂-C₈) alkynyl, (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀)heterocyclyl, arylalkyl, or heteroarylalkyl, wherein each (C₁-C₈) alkyl,(C₂-C₈)alkenyl, (C₂-C₈) alkynyl, (C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl,(C₂-C₂₀) heterocyclyl, arylalkyl, or heteroarylalkyl is optionallysubstituted with 1-3 R²⁰ groups; or when taken together, two R^(y) onthe same carbon atom form a cycloalkyl ring of 3 to 7 carbon atoms; eachR is independently H, (C₁-C₈) alkyl, (C₂-C₈)alkenyl, (C₂-C₈) alkynyl,(C₆-C₂₀) aryl, (C₃-C₂₀) cycloalkyl, (C₂-C₂₀) heterocyclyl, or arylalkyl;R⁸ is H, (C₁-C₄) alkyl, or (C₁-C₄) substituted alkyl; each R¹¹ or R¹² isindependently H, (C₁-C₈)alkyl, (C₂-C₈)alkenyl, (C₂-C₈)alkynyl,(C₄-C₈)cycloalkylalkyl, (C₃-C₂₀)cycloalkyl, (C₂-C₂₀)heterocyclyl,optionally substituted aryl, optionally substituted heteroaryl,—C(═O)(C₁-C₈)alkyl, —S(O)_(n)(C₁-C₈)alkyl or aryl(C₁-C₈)alkyl; or R¹¹and R¹² taken together with a nitrogen to which they are both attachedform a 3-to 7-membered heterocyclic ring wherein any one carbon atom ofsaid heterocyclic ring can optionally be replaced with —O—, —S— or—NR^(a)—; each R¹³ is independently a cycloalkyl or heterocycleoptionally substituted with 1-3 R or R²⁰ groups; each R²⁰ isindependently, halogen, CN, N₃, N(R)₂, OR, —SR, —S(O)R, —S(O)₂R,—S(O)(OR), —S(O)₂(OR), —C(═Y¹)R, —C(═Y¹)OR, or C(═Y¹)N(R)₂; wherein eachalkyl, alkenyl, alkynyl, aryl or heteroaryl of each of R¹, R², R³, R⁴,R⁵, R⁶, R¹¹ or R¹² is, independently, optionally substituted with 1 to 3halo, hydroxy, CN, N₃, N(R^(a))₂ or OR^(a); and wherein 1 to 3 of thenon-terminal carbon atoms of each said (C₁-C₈)alkyl may be optionallyreplaced with —O—, —S— or —NR^(a)—; with the proviso that at least oneof R¹, R², R³, R⁴ and R⁵ is not hydrogen.
 35. A method of treating aviral infection caused by a Flaviviridae virus comprising administeringto a mammal in need thereof a therapeutically effective amount of acompound of claim
 1. 36. The method of claim 35, wherein the virus isselected from the group consisting of dengue virus, yellow fever virus,West Nile virus, Japanese encephalitis virus, tick-borne encephalitisvirus, Kunjin virus, Murray Valley encephalitis virus, St. Louisencephalitis virus, Omsk hemorrhagic fever virus, bovine viral diarrheavirus, Zika virus and Hepatitis C virus.
 37. The method of claim 36,wherein the viral infection is caused by Hepatitis C virus.
 38. Themethod of claim 34 further comprising administering at least oneadditional therapeutic agent selected from the group consisting ofinterferons, ribavirin analogs, NS3 protease inhibitors, NS5b polymeraseinhibitors, NS5a inhibitors, alpha-glucosidase 1 inhibitors, cyclophilininhibitors, hepatoprotectants, other nucleoside inhibitors of HCV,non-nucleoside inhibitors of HCV, and other drugs for treating HCV.